(2018-08-07) Origins of Chess. Ancient and modern rules.
The old games of Chaturanga and Shatranj.
Apart from Go,
all ancien board games can all be classified as single-track race games.
Mancala
is purely strategic (if you're allowed to count the stones in each pit)
but all the others involve an element of pure luck.
Here are the three most notable examples:
The Mesopotamian Royal Game of Ur.
One of the best designs of all time.
It's played with two
sets of seven pieces (at most) racing on a special board of 20 squares
(two symmetrical 14-square tracks sharing an 8-square middle lane).
The game traditionally uses 4 tetrahedral
dice with two marked corners.
The outcome of a throw is the total number of marked corners landing at the top;
it's 0,1,2,3,4
(respectively with 1,4,6,4,1 chances in 16).
The exact rules were found on a late-period
clay tablet from the British Museum
deciphered by
Irving Finkel.
[Play online]
The Egyptian game of
senet (the game of passing).
Two sets of 5 pieces, racing mostly forward on a single 30-square track
(laid out on a 3 by 10 board).
This simple game has been resurrected using the rules reconstructed by the two
game historians Timothy Kendall and
R.C. Bell (1917-2002).
By contrast, the early forms of chess didn't involve chance at all and
made full use of the two dimensions of the game board.
The earliest recognizable form of chess was called
chaturanga (or catur for short).
It appeared in India, in the seventh century AD and is first mentioned in
the Harshacharita
(biography of Harsha,
c.590-647) by
Banabhatta.
Shortly thereafter, the game appeared in Persia under a new name
(shatranj or chatang) and slightly revised rules.
It was possible to win in shatranj by capturing all pieces
besides the King (but it was a draw if the opponent could do the same on the next move).
The strongest shatranj player on record was
Al-Suli (AD 880-946)
the author of a famous shatranj problem known as
Al-suli's Diamond, which was solved in the 1980s
by Yuri Averbakh (1922-2022).
White wins by capturing the black ferz which can only move diagonally one square at
a time) without losing his own on the next ply... in 19 moves!
The starting positions in those games were similar to that of chess
(up to a switch of the king and the minister/general/queen).
However, the pieces had different names, shapes and properties
(somewhat shrouded in uncertainty) as tabulated below.
Pawns capture diagonally. All other pieces capture the same way they move.
Elephants, horses and/or knights jump directly from origin to destination.
For other pieces, a lateral or diagonal move
is only allowed if intermediate squares are unoccupied.
At first, the games were played on an uncheckered board
of 64 squares
The familiar alternating light and dark colors
of modern chessboards first appeared in Europe around 1090.
Some of the boards used were originally intended for an older race game
called ashtapada (eight-legged)
whose exact rules seem lost.
16 special squares called castles were marked with crosses
(at the intersections of ranks 1, 4, 5 and 8 with files a, d,e and h).
Such marks are still found on some chessboards of Indian origin,
although their purpose is all but forgotten.
Fantasy
Legend has it that Chaturanga was invented for Iadava, King of
Telangana,
who was mourning the loss of his son Adjamir.
The Prince had died heroically to secure victory in a decisive
battle at Decsina against the conqueror Varangul.
A young brahmin, called
Lahur Sessa,
walked 30 days from the village of Manir to the
Andhra royal palace
and presented Iadava with the new game he had designed. The king was so pleased
that he asked the young man to name any reward he wished.
The lad made a simple request related to the 64 squares on the board:
He asked for one grain of wheat on the first square, two on the second,
four on the third and twice as many grains on every square as on its
predecessor. The King thought that this was a modest price to
pay, until he was advised that the number of grains so named was humongous:
By convention, the chessboard must be oriented so that the closest corner to the
right of either player is a light square
(light rhymes with right). This was first specified in print by
Pedro Damiano (1480-1544) in 1512.
The practice of shading dark squares in printed chess diagrams was introduced by
the scientist Girolamo Cardano (1501-1576).
Three modern moves have no equivalent in ancient chess:
On its first move, a pawn may travel two squares forward
(if both the destination and the passed-over square are free).
En passant capture
by a pawn is allowed immediately after
one such move (it takes place at the passed-over square). It's customary
to stress such a move with the annotation "e.p." (postfixed) which is entirely optional
since a diagonal pawn move into an empty square can only occur by virtue of an en passant
capture. The option is only open on the very next move, which incidentally
doesn't void the classical way to gain a tempo by putting the king in check.
(A tempo is gained anyway because preventing check is at the cost of an immediate capture.
This is illustrated by
#48875 or
#62178,
where the tempo so gained allows a rook capture (winning the game)
whether the opponent accepts the pawn check or prevents it using en passant.
The rule was primarily invented to prevent the newly-minted two-square pawn moves
to allow too many "passed pawns" (pawns with no opposing pawns on their way to promotion).
Only pawns can capture en passant (other pieces controlling
the square jumped over by a pawn can't capture it en passant,
although it would have been perfectly logical to allow that).
Castling (French roque;
14th or 15th century, in Europe)
If all squares between the king and a rook are free, then
a legal move consists in moving the rook next to the king and having the
king jump over it, provided the following conditions are met:
The king and the rook have never moved before.
No square in the path of the king is under attack.
Two more additions have transformed traditional chess into the game which is most
commonly played today, especially online:
The chess clock. Originally introduced merely
to avoid tournament games that could be so long that they would routinely be
adjourned from one day to the next, the clock
has become such a dominant part of modern games that people routinely win
lots of games merely by outpacing their opponents.
With some silly local rules, a player who doesn't have enough material to
mate may be declared the winner. Arguably, a perversion of chess.
The Elo rating system. It has outgrown its original
purpose to organize tournaments for all categories of players
(you're banned from lower grades when you become too strong).
Improving one's rating may become the most important goal
to achieve. ; At all strength levels from utmost beginner
to World champion (World champion Magnus Carlsen
once stated that his top priority was to achieve an Elo of 2900 rather than
retain his World title).
In 1972, the journalist
Tim Krabbé (1943-)
composed, as a joke, a
chess
problem whose solution involves a vertical castling
on the "e" file using a rook created by pawn promotion which had never moved!
Krabbé even put forth the notation O-O-O-O
for this hitherto unused third type of castling.
Shortly thereafter, a new wording of the laws of chess was enacted to disallow that.
Chess used to be played until the king was actually captured.
This meant that a player who didn't move out of check
(or even moved into check) would lose by having the king captured
on the next turn, unless the opponent blundered the game away.
To avoid such endings,
it's now illegal to move into check or not to move out of check.
To better enforce that law, whoever puts a king in check must announce it.
In several languages, the plural form of such announcements morphed into the name
of the game itself (chess is a corrupted form of
checks in English; the game is called
échecs in French).
One interesting consequence of that modern rule is the possibility of
stalemate (French: pat) which
is a situation when a player is not in check but has no legal move available.
This is now declared a draw.
In some endgames, the goal of the dominating player
thus becomes to force checkmate while avoiding a stalemate situation.
Some obsolete rules considered a stalemate
a win for whoever was called to play from such a situation.
This was the case in England until 1800.
The German term Zugzwang
(capitalized if German spelling is to be respected) denotes a configuration which
is less favorable if you have to move first than if you don't, especially in endgame
situations very near to a checkmate or stalemate.
(In combinatorial games theory
the term is sometimes used to denote a losing situation for whoever has to move first.)
The oldest extant
game of modern chess was played in 1475 in
Valencia between
Don Franci de Castellvi (White) and
Narciso Vinyoles (Black).
The game illustrates a famous poem entitled
Scachs d'Amor
(Chess Game of Love) written in Catalan (more precisely
Valencian)
by Castellvi (Venus), Vinyoles (Mars) and
Mossèn Bernat de Fenollar (Mercury).
Caissa (pronounced ky-eé-sah) is
a nymph of Greek mythology
who became known as the patron godess of chess after a celebrated
poem written
in 1763 by the young
William Jones
(1746-1794) and entitled
CAISSA or The Game at Chess; a Poem.
The poem of Jones was itself inspired by a
658-line poem
in Latin called
Scacchia Ludus (The Game of Chess) due to
Marco Girolamo Vida
(c.1485-1566) who wrote it around 1513,
as Chess in its modern form was gaining popularity in Europe.
It was first published anonymously in 1525 before appearing officially
under Vida's name in 1527.
(2018-09-11) Chess Tables, Boards and Mats.
Various ways the actual chess playing surface is provided.
The generic term of chessboard (or just board)
is used for all of these, but it need not be an actual rigid board.
It can also be inlaid into a dedicated table or, for best portability,
a mat can be used which can be rolled up (or folded, if made out of silicone).
In the US, the most common size for tournaments features 2.25''
squares (57 mm). In metric countries, it's nominally 55 mm.
The playing surface itself is thus 18'' (46 cm).
Typically about 20'' with the borders which often
feature two sets of rank numbers and file letters (to accomodate both players).
Smaller boards are 2'' (51 mm) or 50 mm.
Larger ones are 60 mm. (about 2 3/8 )
rarely 2.5'' (63.5 mm).
Anything outside that range is unsuitable for competition
(especially for quick
bullet games).
Among many others Wholesale Chess offers 60 mm mahogany-and-maple boards for
$80
or
$90
(with notation). The playing surface on those boards is exactly 19''.
They measure 21½'' with the borders.
I love the look and feel of a borderless regulation board
(2¼'' = 57 mm) which spans only 18½''.
(If borders with notation are ever needed, such a board can be placed
on top of an ordinary tournament mat.)
The best-bang-for-the-buck I found is the inlaid mahogany and maple
Zelus
chessboard
($55)
which comes double-boxed for shipping
(Amazon even puts that double box in an oversized shipping box of their own.)
Such high-quality borderless chessboards can also be used in a customized table
or a one-of-a-kind frame (the playing surface can be mounted recessed, flush
or raised, according to taste).
That's a cost-effective way to bypass the time-consuming process of
finishing a good playing surface by hand.
If you make your own frame, consider
providing some substantial rounding or overhang on the outside edges to make
the assembly easy to pick up (most commercial products don't).
Arguably, the board need not match the colors of the pieces.
Playability is hindered when ebonized pieces are
camouflaged on black squares.
Husaria #6 Chessboard (57mm = 2¼'')
maple and padauk
($45).
Polish #5 Chessboard (50mm = 1.97'')
mahogany and sycamore
($45).
When the game of chess is discussed abstractly,
we talked about pawns and pieces.
The word chessmen is normally used only for
the physical objects made from wood, metal, stone, clay or plastic.
In modern tournament play, only minor variants of the
Staunton chessmen are used.
The official tournament guideline states that the base diameter of the king should be no more than 75%
of the side of a squares on the chessboard.
Four pawns should barely fit into a square (base diameter being 50% the side of a square).
My own plastic tournament set, for use with a standard 2¼'' mat,
is the common 3.75'' Staunton design
highlighted above.
With the slim Zagreb '59 design, a tall king (3.9'')
can fit nicely on a standard 2¼'' board.
I bought the new weighted boxwood set shown below off of eBay directly from India
(for $68.64,
including expedited shipping from Amritsar to
Los Angeles).
It arrived in less than 4 days.
The above picture shows 2'' squares, which are a bit too small for
the Zagreb pieces whose precise measurements are listed below:
Zagreb '59 Measurements (3.9 '' nominal)
Mass
Height
Base
King
57 g
3.87 ''
98.3 mm
1.69 ''
42.8 mm
K
Queen
53 g
3.50 ''
88.9 mm
1.59 ''
40.5 mm
Q
Bishop
39 g
3.08 ''
78.2 mm
1.42 ''
36.0 mm
B
Knight
46 g
2.78 ''
70.5 mm
1.45 ''
37.0 mm
N
Rook
38 g
2.23 ''
56.7 mm
1.43 ''
36.3 mm
R
Pawn
17 g
1.99 ''
50.5 mm
1.20 ''
30.4 mm
P
Matching Square Size
2.25 ''
57.2 mm
S
This stylish East-European design is a major variant of the Staunton style.
The Zagreb design is characterized by counterchanged
finials and
distinctive
square-fronted Russian knights.
The bishops have unslotted tops in the shapes of the
bulbous miters
worn by bishops of the Eastern Orthodox Church.
They differ from the splitted pointed Western miters of the
Roman Catholic Church, which inspired the slots
of the bishops in the original Staunton pattern.
The Zagreb design was launched on the occasion of the
1959
Candidates Tournament held in
Yugoslavia, in
Zagreb (capital of Croatia)
Belgrade (Capital of Serbia)
and the touristic town of Beld.
Eight leading contenders
(including Bobby Fisher, then 15 years old)
were competing for the right to challenge
the reigning World ChampionMikhail Botvinik (1911-1995)
for the crown he had been holding continuously since 1948,
with a single interruption in 1957-1958.
The legendary Mikhail Tal (1936-1992)
won and went on to fetch the World title the following year, in Moscow,
but lost the rematch in 1961.
Tal remained popular well after that. So did the Zagreb pieces.
I got this chess set in spite of the blocky aspect of its knights,
which turns out to be an acquired taste. It's now my favorite set to play with.
The ideal square size for a given set of pieces depends only on the bases,
not the heights. Two good rules of thumb are floating around.
The first one is simple but the second one is more robust and
more general (it applies to all round designs, even outside the Staunton family):
The king base should be about 75% of the side of the field square.
If a king and a queen are diagonally adjacent,
the distance between them should be greater than the bishop's base.
The latter rule allows play by sliding the pieces even in the worst possible
case (when a bishop moves between the two largest pieces which can
legally be adjacent to each other). If that's your preferred style,
this should be the primary consideration and
the ensuing inequality must be satisfied with some room to spare
(to allow for misalignments during actual play).
Usually, even people who like sliding the pieces will lift them
when the squeeze seems tight.
Two unreliable criteria are used by some salespeople:
The square should be twice the base of the pawn
(i.e. 4 pawns can fit in a square) or half the
height of the king (i.e., a fallen king spans two squares).
The first rule corresponds to the rough formula K = 0.75 S.
The second one says that the diagonal of the square must be
greater than the bishop's base plus half the sum of the king and queen bases.
Namely:
S Ö2 > B + (K+Q) / 2
For the above dimensions of the Zagreb pieces, those two formulas give:
S = 2.25 '' or 57.2 mm
S > 2.16 '' or 54.9 mm
This does indicate that a regulation chessboard
(55 or 57 mm) is nearly ideal for the above zagreb pieces
(while a 2'' board is definitely too tight).
Let's do the same computation for the tournament plastic set I use:
Classical Staunton Measurements (3.75 '' nominal)
Mass
Height
Base
King
68 g
3.70 ''
93.9 mm
1.79 ''
45.4 mm
K
Queen
62 g
3.12 ''
79.2 mm
1.71 ''
43.5 mm
Q
Bishop
37 g
2.78 ''
70.6 mm
1.43 ''
36.3 mm
B
Knight
41 g
2.40 ''
61.0 mm
1.38 ''
35.1 mm
N
Rook
46 g
2.21 ''
56.1 mm
1.50 ''
38.1 mm
R
Pawn
22 g
2.07 ''
52.6 mm
1.26 ''
32.0 mm
P
American Regulation Square
2.25 ''
57.2 mm
S
The aforementioned guideline formulas would give:
S = 2.39 '' or 60.6 mm
S > 2.25 '' or 57.2 mm
Thus, those pieces can be played on regulation US mats (57.2 mm).
An oversized 60 mm board would be fine too.
Our next example involves the French style which was dominant throughout Europe before
the Staunton pattern displaced it for serious play.
It's best called Régence.
Drop the accent if you must, but avoid the Regency misnomer,
since this chess style was actually named after what was the undisputed nevralgic center of
Chess in the eighteenth century:
Le café de la Régence in Paris, France
(best left untranslated).
Incidentally, Howard Staunton (1810-1874) crowned himself
World champion in 1843,
when he won his return match against the most prominent Régence
player of the time, Pierre Saint-Amant (1800-1872).
Traditionally,
Boxwood was used for white pieces and ebony
for black pieces.
Both kinds of wood are denser than water with very fine grain which makes
them exceptionally well suited for turning and fine carving.
Because of recent restrictions on the harvest of ebony,
boxwood is increasingly used for black pieces as well using
what's call ebonization, which
can be done several different ways.
Black color is obtained when ferric acetate
reacts with wood tannin. This reaction uses the same basic principle
as iron-gall ink
(upon which Western civilization was arguably founded).
To make a good ebonizing solution at home,
first clean some steel wool thoroughly with soap and water
(to remove any trace of oil which would hinder the rest of the process).
Rinse it well.
Let it soak for several days at room temperature in a mixture of cleaning vinegar
(6% or 8% acetic acid) and hydrogen peroxide
(heating can speed up the process, if needed).
Ferric acetate will form:
The bag I recommend to carry full-sized pieces,
a rolled-up mat, a clock,
scoresheets and pens is from the USCF
($25).
(2018-08-07) Chess Clock
Some controversial aspects of timed games.
Time limitations on chess games are of relatively recent origins.
Chess clocks have been used in competition since the London International Tournament of April 1883.
In official FIDE tournaments, the chess clock always sits to the rignt of whoever
plays with the black pieces.
Time controls were born out of necessity to make the organization of tournaments possible.
The possibility of losing on time was originally just
a way to enforce those time limits without altering the nature of the game.
Bonus and Delay :
Those are the two simplest ways to force fast play on low time without
making it humanly impossible to execute decent moves.
In practice, these two methods are never
used together (although they're not incompatible).
Bronstein delay is also called simple delay
or US delay.
The player's alloted time doesn't start to be debited until a certain
preset delay has ellapsed.
A player who plays every move faster than this
preset delay will never run out of time.
Fischer increment is a preset bonus time
which is added at the beginning of every turn.
The unused portion of those bonuses can accumulate so that
a future move which requires more consideration can be played less recklessly.
Currently, almost all classical chess tournaments endorsed
by the Worldwide Chess Federation are played in
90 minutes (per player) for the first 40 moves and 20 minutes
for each side for the rest of the game,
with a 30-second Fischer increment per move
(starting with the very first move).
That gives each player 110 minutes to complete the first 40 moves.
(That's code 04 on the Wholesale Chess Advanced Digital Game Timer.)
For the World Championship (and the qualifying Candidate Tournament)
the time limits are 100 minutes for the first 40 moves, 50 minutes
for the next 20 moves and 15 minutes for the rest of the game.
Again with a 30-second Fischer increment starting at the first move.
(That's code 05 on the Wholesale Chess Advanced Digital Game Timer.)
Japanese Byo-Yomi:
This is a more complicated time-control used for mostly for
shogi and
go but
digital chess clocks often allow it.
Gentleman's Rules:
It's a monstrosity to grant a win in chess to a player who doesn't even have enough
pieces to mate (although it's sometimes done in automated online play).
In that case, a player is awarded a draw if the other runs out of time.
The game is an instant draw if neither player has enough to mate.
Furthermore, a good Gentleman's Agreement
in a timed game is to resign with a bare king if the other side has at least:
A queen.
A rook.
Two bishops.
A bishop and a knight.
It would be nice if chess-playing software enforced this automatically.
In over-the-board play, someone who grabs a piece which has at least one legal move
must play that piece (the old-school touch-move rule).
A legal move is final when the player lets go of the piece.
I argue that no penalty should be incurred when an illegal move is corrected
before the clock is punched
(but punching the clock after an illegal move forfeits the game).
(2022-02-07) Naming the 64 squares of the Chessboard
By far, the most common way is the algebraic one. Others still exist.
(2018-08-13) Standard algebraic Notation
(Philipp Stamma, 1737)
Only one notation survives to record chess games, with minor variants.
Each square is identified by a lowercase letter from "a" to "h" according to
its file and a numeral from "1" to "8" according to its rank.
Squares are either light or dark.
The corner squares to the right of either player (h1 and a8) are light.
In the starting position,
the white queen is on d1 (a light square) and
the black queen is on d8 (a dark square).
You may want to remember that queens start on their own colors.
Each type of piece (besides the pawns) is identified by a single capital
letter: K, Q, B, N, R
(at each move, White moves first and Black second).
When a piece is not specified, a pawn move is understood
(the abbreviation P is deprecated).
In case of ambiguity (when the landing square is accessible to two like pieces)
give the lowercase letter identifying the file (column)
where the piece is moving from after the name of the piece.
If that doesn't lift the ambiguity, give the number of the rank instead.
Conceivably, you might need to name the starting square fully, by file and rank,
in the extremely rare case where the destination square is accessible to three
like pieces at the corners of a rectangle. Prerequisites for such a situation include
a promotion to knight, two queenings or two promotions to bishops!
Yet, if you're a programmer, you must anticipate such a weird thing.
Long and short castling
are respectively denoted O-O-O and O-O.
When a pawn is promoted, the piece it becomes is indicated after an
equal sign (formerly, a slash was used).
For example: 67. c8=Q
No special notation is used (or needed)
for en passant capture.
A move which puts the king in check is followed by a plus sign (+).
Checkmate is indicated by a pound sign # (++ is deprecated).
In the computer era, it's important to always record moves in the tersest way
(so plain text searches can fetch them). However, in handwritten or printed
scores, it's nice to name the captured piece for the sake of readability.
For example, the key move in Legal's mate
could be written :
5. Nxe5 BxQd1
Likewise, one of six abbreviated
annotations
of one or two characters, can be given after any move, except a checkmate
or a forced move.
Brilliant (!!).
Excellent (!).
Debatable (!?).
Dubious or inaccurate (?!).
Mistake (?).
Blunder (??).
This is in addition to the automatically affixed qualifiers not subject to any judgement call:
Check (+). Marks a move that would allow capture of the king on the next turn.
Double-check (++). In check by two different pieces, the king has to move.
Forced (,). Only legal move. (Optional but helpful symbol, replacing the tombstone.)
Checkmate (#). The king is in check and can't get out of it. Game over.
Single-line (,,). Obvious or sample choice (the other possibilities needn't be discussed).
This may also mark an irrelevant waiting move
or one of several moves which vacate the same square in a discovery attack.
A double-comma indicates two or more options. More than two commas must indicate the exact number of those options.
The above use of single or multiple commas as symbolic comments after a move was my own proposal. (2022-02-20).
Some authors have used a typographical
tombstone for both purposes,
often without making a clear distinction between forced moves and single line.
The commas are, of course, available directly from the keyboard are are thus painless to use.
They are unobtrusive enough so that they can sometimes serves a similar purpose but
some authors employ that to indicate what they think is the only reasonable move.
Commas are unobtrusive enough to be ignored by the uninitiated.
Yet, a commonly available punctuation mark for forced moves was logically needed
(it's a routine comment for which none of the other comment symbols apply.
Note that other punctuation marks which were not available for the purpose include
the semicolon (;) which is already codified to indicate in computer
notation that the rest of a line is comment directed at human readers.
Unfortunatey, the names of the pieces and their abbreviations are different
in different languages (in addition, following Maurice Beaucaire,
the French used to replace "c" and "e" by "ç" and "é" for in square coordinates, to help distinguish the two).
For international communication, graphical hieroglyphs for the pieces are often used in print,
although I find them harder to read (if your eyes are on the wrong side of the half-century mark).
English
K
Q
R
B
N
(P)
French
R
D
T
F
C
(P)
German, Dutch, Swedish
K
D
T
L
S
(B)
Italian, Spanish
R
D
T
A
C
(P)
Portuguese
R
D
T
B
C
(P)
Czech
K
D
V
S
J
( )
Reversible (long) notation :
Formerly, both the origin and destination were always recorded.
This convention is now fairly rare. It's known as long
or reversible because it makes it easy to move back from a position
given in a diagram (especially since the names of captured pieces are always
given with the destination square). For example:
(2018-08-13) The most common chess openings:
An advanced player's repertoire consists in familiarity with many lines.
White has 20 possible first moves (2 per pawn and 2 for each knight)
corresponding to the 20 headings below, listed in order of popularity.
Because the Sicilian Defense (1. 1. e4 c4) is so strong,
the second-most-popular opening move for White (1. d4) can be considered stronger
than the most popular one (1. e4) whose continuations take up more space in this
list than all the other variations combined.
This structured list introduces the names
of some notorious openings discussed among players.
The Oxford Companion to Chess goes well beyond this, with
1327 named opening lines.
A given situation can often be obtained by executing the same moves in different orders.
In that case, the resulting variations are said to be transposed from each other.
For example, the Nf3 variation of the Scandinavian defense transposes to a Zukertort opening:
(2021-12-20) Ragozin Position
A position commonly reached from severalopening lines.
Reaching the same position through the same half-moves played in different orders
is of course a common thing, called transposition in chess jargon.
After the second move, this is the rule rather than the exception.
For cultural and historical reasons, the Ragozin position is normally
studied only under the name of
Ragozin defense
as a variation of the Queen's Gambit Declined corresponding to the first of the
lines enumerated below, to which other transpositions usually refer to;
A chess diagram merely describes the positions of the various pieces on the chessboard.
whereas a chess position also includes information about
castling and en passant privileges.
(The terms configuration or situation are used here to cover
either concept indifferently.)
The two enumerations start to differ after two full moves (four plies) when
a white pawn is on rank 5 with a black pawn to its immediate right or left
(and any other black move played elsewhere).
In this case, White has en passant privileges for the third move
only when that side pawn arrived there on the second black move.
A complete position consists of a chess position
and a ply number (odd only when it's White's turn to play).
Transposition tables in chess-playing software typically
contain only positions with ply-parity (indicating whose term it is to play)
although complete ply information would be needed to properly deal
with draws by repetition and apply the
50-move rule
(and/or the new automatic 75-move rule,
officially introduced in 2014).
In the case of the above enumeration, the ply number is given a priori,
so the mere position fully determines the complete position.
Les pions sont l'âme des échecs. André Danican
Philidor (1726-1795)
Enumerating one-sided pawn configurations :
Pawns can occupy only 6 ranks (the first and last one are ruled out).
If they were only alloed to go straight, there would
only be C(8,p) 6p
configurations of p pawns (0≤p≤8). This adds up to
78 = 5764801
possible configurations. That number is thus a lower bound
to the total number of configurations. (One quick way to obtain this resulat
is to consider that there are 7 possibities for each file; either no pawn or a single
pawn in one of the 6 allowed ranks).
On the other hand, we can obtain an upper bound by allowing the p
pawns distinct positions anywhere in the 48 squares where they can be.
That's C(48,8) = 377348994.
Thus, the correct number is between 5 and 378 millions.
Actually, the p pawns may have been involved only in
a total of c captures (c≤0≤15-p). Some leftward,
some rightward.
Our first lower bound is actually the exact count when c = 0.
Upper bounds to the number of possible chess diagrams
To find a fairly tight upper bound, we start by the exact number of ways to place the two
kings so that they're not next to each other.
Then, we'll place all possible remaining pieces on the other 62 square.
This does leave some impossible postions (for example,
when both kings are in check) but relatively few. Also, there are
diagrams which are notoriously unreachable for nontrivial reasons.
Most notorious;y the two-knight checkmate. (what could the previous move have been?)
A white king on one of the 4 corners rules out 4 squares for the black king.
A white king on the rest of the border (24 squares) rules out 6 squares for the black king.
A white king on one on the 36 inners squares disallows 9 squares for the other king.
All told, the number of ways to place the two kings on non-adjacent squares is:
4 × (64-4) + 34 × (64-6) + 36 × (64-9) = 3612
That's a 10.4% improvement on the number of ways to place the
two kings on twi different squares d (64 × 63 = 4032).
(2021-12-18) Single-byte encoding of most half-moves in chess.
This code includes the name of the moving piece.
The encoding scheme described below is able to specify any legal move
(and a number of illegal ones) for a given player in a known diagram,
sssuming only that there are fewer than four pieces of each type.
In pathological cases exceeding that limit, the scheme may call for two bytes to
specify some oves involving a piece with too many twins.
Each side always has only one king and never more than eight pawns.
Each piece other than the rook ansd pawn is identified by a numebr from 1 to 3
among its twins as they occur on the board reading line by line from top to bottom and right
to left. It does take some thinking to pack all the information required
in a single byte in such a way that it can be decoded without ambiguity.
There is not enough room to allow for more than 3 pieaces of each kind.
The leftovers in the decoding process are used to encode special moves like
castling, resigning and offering a draw as well as an exception hanling mechanism
to allow escape to a second byte of code whan abolutely necessary in
the aforementioned pathological cases with many pieces of the same type
(an 10-bit code is then used whose top two bits are embedded in the leading byte).
Different single-byte half-move codes :
B7
B6
B5
B4
B3
B2
B1
B0
Second-byte extension
Queen
1
1-3
b/r
D
1 to 7
10-bit codes
are only used when there are 4 or more like pieces.
King
1
1
K-Move
000
10-bit
1
0
1
E9
E8
000
E7
E6
E5
E4
E3
E2
E1
E0
Pawn
1
00
Move
0-7
Under- promotion
Piece
Move
Rook
0
1-3
1
D
1 to 7
Usual promotion to a queen is just denoted
by an ordinary (nonzero) move to the last
rank in a single byte.
A zero move just indicates the presence of
an extra byte containing the actual
(nonzero) code and the code for the piece
you're under-promoting to.
The only other use of a zero-code move
is to denote a two-square jump as the
initial move of a pawn.
Distance traveled along a direction (D) for long-range pieces is a nonzero number (1-7)
understood modulo 8 (thus possibly as a negative number when the positive interpretation
falls off the board. Thus, for the horizontal motion of a rook, the following code
applies where only one occurence of the two possible meaning of a 1-7 code is valid,
as the other is off the board.
Horizontal rook-move shows how only one value of a 1-7 displacement is valid.
001
010
011
100
101
110
111
001
010
011
100
101
110
111
Example, when on file "c":
a
b
c
d
e
f
g
h
Vertical rook-move shows how only one value of a 1-7 displacement is valid.
001
010
011
100
101
110
111
001
010
011
100
101
110
111
Example, when on file "3":
1
2
3
4
5
6
7
8
Likewise, there are two kinds of bishop moves:
Ascending (D=0): Vertical and horizontal displacements are equal.
Descending (D=1): Those two displacements are opposite.
.
The board is always shown as White normally sees it:
White pawns only move upward, black pawns go downwards.
There are three ordinary (nonzero) types of pawn moves. All one square forward
possibly diagonally (to the left or to the right) in case ofcapture.
The zero move is either a two-square jump from the starting rank or an under-promotion
(a pawn being promoted to any piece other than the usual queen).
In that case, the next byte contains two bits specifying the true (nonzero)
pawn move and two bits encoding the desired piece
(rook, bishop or knight). That's to say nine possibilities
encoded in four bits (and four unused bits).
Extra byte is almost never called for :
The special extended "10-bit code" contains 2 bits of data in the leading byte
and 8 bits from the following byte.
Four of those bits are used to specify which of the 16 pieces
is to be moved (each player has at most 16 pieces on the board).
The other 6 bits specify the desired relative displacement modulo 64.
As this can't be zero, the extra byte is never zero and we can be
sure that a zero byte cannot occur in an encoded sequence of chess half-moves,
except as an endmarker.
This makes it trivial to skip an entire sequence of moves to access
the rest of the data.
Can we do better ?
Yes, very much so. From any chess position
(including diagram, turn, castling and en passant information)
we can use a fixed procedure to generate all the possible legal moves and simply
specify the index within that list of the move to be played.
Even better, we don't need to specify a fixed number of bits for each half-move
but simply encode the whole sequence of moves as a (large)
number N. from a given position, we may generate the p possible
moves. The index in that list of the first move to play is N mod p
and the code for the rest of the sequence is (N-m)/p. An so on
until the code for the remaining sequence is 0 (no more moves to play).
Acknowledgment :
In a draft put online on 2002-07-26
(revised 2003-12-26, 2006-07-19, 2006-10-22 and 2013-02-26)
Norman Brenner proposes to encode a chess half-move
in a single byte (8 bits). Unfortunately, his method uses one more bit than necessary
to describe the moves of long-range pieces (bishop, rook and queen)
which makes his claim (up to 4 pieces of the same kind on the boad)
utterly impossible to achieve. Even with our more compact coding for long-range pieces,
a single it's impossible to handle more than 3 pieces of the same kind in a single byte.
uses 6 bits to describe move of a queen
(2022-01-14) Fairy byte encodes moves without naming pieces.
A more practical approach is more flexible, with improved generality.
Different single-byte half-move codes :
B7
B6
B5
B4
B3
B2
B1
B0
Second-byte extension
Queen
1
1-3
b/r
D
1 to 7
10-bit codes
are only used when there are 4 or more like pieces.
King
1
1
K-Move
000
10-bit
1
0
1
E9
E8
000
E7
E6
E5
E4
E3
E2
E1
E0
Pawn
1
00
Move
0-7
Low Queening
Piece
Move
Rook
0
1-3
1
D
1 to 7
Usual promotion to a queen is just denoted
by an ordinary (nonzero) move to the last
rank in a single byte.
A zero move just indicates the presence of
an extra byte containing the actual
(nonzero) code and the code for the piece
you're under-promoting to.
The only other use of a zero-code move
is to denote a two-square jump as the
initial move of a pawn.
(2007-07-01) Nalimov computer tables for endgames with few pieces.
Tabulating all positions is an efficient way to solve an endgame perfectly.
If the total number of game positions is small enough,
then each of them can be allotted a small computer record in an explicit table.
The entire game can then be solved efficiently by analyzing that
table top-down
(first completing the records corresponding to final positions, like checkmates).
For the game of chess, this is practical only in endgame situations,
when only very few pieces remain on the board.
A database is a set of stored key/value pairs, where only
a small portions of the possible keys exist (for example, not all possible
surnames exist in a database of people whose names are used as "keys").
By contrast, a tablebase includes (almost) all
keys. The key itself need not be stored in a tablebase; it's merely used
to compute the unique numerical address where the information corresponding to
that key is located.
In game tablebases, the game position is the "key" used to access the
value recorded in the tablebase.
By contrast, in a data base, only a tentative address can be computed,
based on a so-called hash-code which a key
may share with many other possible keys.
The location computed from
the key's hash-code is merely a starting point where a whole list of keys can be
found (with their associated recorded values). When a database is queried
for a key, the query key must be compared with the stored keys.
The size of a database containing n different keys is thus more than
n lg n bits. (A tablebase which associates a single bit
to each of n possible keys has a size of only n bits.)
Perfect play is defined as achieving victory as fast as
possible, or delaying defeat as much as possible. A full analysis of the
game is normally possible only by recording the length of a perfect game for
each tabulated position (the position is a first-player win when that length
is odd, it's a first-player loss otherwise
(the issue of ties is discussed below).
A computer database which gives the number of half-moves to the end of a
perfectly played game is called a Nalimov table.
It's easy to play perfectly by looking up such a table:
Play into the smallest even position if you can, otherwise play into the largest
odd position. A special label must be assigned to ties which is
adequately defined as an odd number larger than any other...
(for example 255, if Nalimov records consist of a single byte).
There is no notion of "perfect play" for a game which ends in a tie.
Such a game is merely considered equivalent to a game which goes on forever
because neither player can force a victory.
Yet, it's possible to refine Nalimov values to distinguish between
a tie "by the book" (which tells that an undecided game is over)
having the highest odd value and other ties which have odd values just below
that (but above any other odd values corresponding to true
first-player wins).
Error-free play (as opposed to perfect play)
can be defined as what happens when neither player gives up victory
when it's available to them.
It is not required of the winner to force a quick conclusion.
A practical "tie" may even result if victory is postponed indefinitely
(a win may thus be transformed into a tie by the actual rules of
chess which limit the number of capture-free moves).
Compact bit-wide tablebases, known as bitbases, are sometimes used
in actual chess-playing programs as "oracles" which help make error-free decisions
in the endgame.
A single bit is assigned to each position whose value is
zero (0) if and only if it is a first-player loss.
The value "1" corresponds to a first player win if and
only if it has at least one option labeled "0" (otherwise,
the "1" indicates a tie).
A bitbase (for mere error-free play) is normally obtained by
extracting the relevant information from a complete Nalimov table.
Eugene Nalimov
was born in Novosibirsk in 1965. He joined Microsoft as a programmer in 1997,
he later joined the Seattle-based Context Relevant startup
(called Versive since 2017).
Nalimov started writing tablebases generators for chess endgames in 1998.
He was honored for that work by
ChessBase
at their 2002 convention, in Maastricht.
Example: The Knight and Bishop Endgame
The basic table base (TB) only needs to consider the positions where the bishop
is on one of the 16 topmost white squares. Ignoring obvious illegal
positions (e.g., several pieces on the same square or adjacent kings) the other
pieces can be on one of 64 squares and it can be the turn of either
Black or White. All told, the size of the TB,
at one byte per position, is fairly small:
2 . 16 . 64 . 64 . 64 = 8 MB
Each of those bytes just contains the number of moves to mate.
Well beyond what humans can compute :
Ignoring the 50-move rule, starting from this position
White can mate Black in 94 moves.
The only winning move is Ke3!!
Kde-e3 !! Kh2-g3
Against another reply,
White can mate in at most 10 moves (instead of 93).
(2021-21-31) King and knight vs. king and pawn.
Color matching required to mate a cornered king with a knight.
In the folloing diagram, when the white knight is on a numbered square opposite to the color
of the cornered black king it can mate it in the number of moves so indicated.
Mate can only be delivered from a last move from the only square numbered "1" (c1)
to the unique square numberd "0" (b3). When on c1, the knight puts the king in check,
so the only black move available is to advance the pawn to a2, cornering the
king which is checkmated when the knight moves to b3.
If Black were to choose to advance the pawn before being forced to do so that way,
the white knight would be on a dark odd-numbered square and could deliver mate
by moving directly to b3.
Otherwise, the strategy is simply for the knight to move from a numbered square
to a numbered square with a lower number. Moving to another numbered square
simply delays the mate. The knight can ultimately deliver checkmate
if and only if it moves from the same solor as that of the black king.
If the knight is on the wrong color,
there can never be a checkmate even if Black cooperates.
If the knight isn't on a numbered square,
Black will have an opportunity to force stalemate by advancing the
pawn when a2 is free and the knight is too far to check.
8
7
4
4
6
4
4
4
5
5
3
4
4
4
6
3
4
3
0
2
4
2
5
2
1
6
1
6
a
b
c
d
e
f
g
h
The above is the basis for some chess puzzles composed before
the first publication of Bonus Socius
compilation (around 1266). The changes in the rules of chess since that
time didn't affect kings, rooks, knights and pawns (except on their first moves).
Also, the single line given below (which leads to a different mating position)
can be used when the pawn is as high as a4.
No such thing exists for a5 or above,
because that would entail a possibilty for the pawn to capture the knight or for the black king
to escape to b4.
If N starts from a6, c6, d5 or d3 (shown left).
Mate in 3
Nb4! a3
Kc1 a2
Nc2#
Checkmating Chases :
The above is perhaps the ultimate example of a chase ending in checkmate which the winner can only
lengthen and the loser only shorten. Few chases has this feature and it's difficult
to define precisely what a chase is but you know one when you see one.
Here are examples from real archived games:
#2FdzU (1847) .
27...Qh2+? would be a mistake instead of 27...Bh2+!
(2010-01-28) Static Evaluation Function
Evaluating quiescent positions is an art form.
Relative values of chess pieces according to various authors :
P
N
B
B'
R
Q
André Danican Philidor, 1777
1.00
3.00
3.50
4.00
5.50
10.00
Peter Pratt, 1799
1.00
3.00
3.00
3.00
5.00
10.00
Larry Evans 1958
1.00
3.50
3.50
4.00
5.00
10.00
Maurice Beaucaire, 1967
1.10
3.00
3.00
3.50
5.00
10.00
Bobby Fisher, 1972
1.00
3.00
3.25
3.75
5.00
9.00
Garry Kasparov, 1986
1.00
3.00
3.15
3.65
4.50
9.00
Hans Berliner, 1999
1.00
3.20
3.30
3.80
5.10
8.80
Larry Kaufman, 1999
1.00
3.25
3.25
3.75
5.00
9.75
With the only possible exception of the earliest one (Pratt) all the above authors
have pointed out that a pair of bishops is worth more than twice the value of a lone bishop.
When pressed to quantify that bonus, they reluctantly say it's about half a pawn
(50 centipawns). In the above table we added that bonus (0.5 by default)
to the value of the second bishop, denoted B', which is mathematically equivalent.
A knight and a bishop are better than a rook and a pawn.
Three minor pieces are better than a queen.
Endgame evaluations :
A radical method would be to consider the ability to mate of certain combinations of pieces against others,
measured by the maximum number of moves needed to resolve the situation to a mate
(as obtained from Endgame tablebases):
There are 8 variations which result in a position similar to
the one depicted at right, where White is checkmated.
They differ by the order White moves his two pawns and also by two
possible choices for moving the central pawns of each player
(one square or two squares).
The locution fool's mate is sometimes used as a generic term
to denote any very early checkmate, especially the following one:
This mate is often attempted among newcomers.
The French call it le coup du berger which translates
literally as Shepherd's mate, as do the names of that checkmate
in several other languages, including
Spanish,
German,
Dutch and
Portuguese.
The fool's mate and scholar's mate
may well be as old as chess itself but they were apparently not mentioned in print before
the seventeenth century,
as they found their rightful place in the early classification
proposed by one Arthur Saul
in "Famous Games of Chesse-play" (1614).
Counting the number of 4-move games ending in a scholar's mate
can be an interesting exercise: The game may end with Qf3xf7#
(e.g., after the infamous
Napoléon
opening) or Qh5xf7# (as above).
In either case, White can play in 4 different ways
(opening with either e3 or e4, then moving either the bishop or the queen).
Each sequence makes different "compatible" moves available to Black.
If the black queen moves, she must move back. To allow the mating move,
the white queen's path must be clear and f7 must be unprotected...
(2021-12-11) The quintessential chess puzzle: Find mate in N moves.
The challenge may be to prove one can checkmate in N moves or less.
Checkmate is the situation when the king is in check and cannot get out of it.
That would mean that it couldn't avoid capture on the next move if the games was allowed to go on.
Under modern rules, a checkmate ends the game.
Originally the purpose of chess was to capture the king, but requiring a proper checkmate
makes careless play illegal where a king is captured when it had a way to escape.
Both players are responsible to verify that a checkmate is valid.
Therefore, being able to recognize checkmate (and also stalemate)
is a prerequisite to play chess. It just as basic as learning
how the pieces move, albeit a bit more difficult.
Chess would essentially be the same game it is was allowed to proceed till the
actual capture of the king, as was the case in the old days.
Except that stalemate would still be a win instead of a draw, as it is today.
(The status of stalemate as a draw makes some endgames more interesting but
it's what prevent chess from being a normal game;
the qualifier which says that whoever has no legal move loses the game.)
The only recorded outcome in competitive chess is win, lose or draw.
However, in the world of chess puzzles, best play is always meant
to force chackmate in as few moves as possible against an opponent doing his best to delay it.
There is absolutely no other measure of the value or beauty of a game of chess beside this. Ever.
In particular, the pieces still on the board of a finished game have no value whatsoever.
In fact, some admire instead the skill of a player who was able to win the game by cleverly
sacrificing pieces to achieve checkmate. One of the most famous example is
what's known as the immortal game.
Here, White just queened with check. Clearly Black should have resigned a long time ago.
The challenge for White is to arrive at a checkmate on his third move or earlier.
The problem is to find the winning move (there's only one).
Mate in 3
1. Bd8+ Kc6 2. Qf6+ KxN 3. Qb6#
1. Bd8+ Kc6 2. Qf6+ Kb5 3. Qb6#
1. Bb8+ Kc8? 2. Bb6#
The third variation ended earlier because Black didn't play well.
An ancient mate-in-2 puzzle
There's only one solution: Rg7!!
(It's much easier to mate in 3...)
This appears in the
Bonus Socius manuscript (c. 1266).
However,
the following analyzed game illustrates a bold counterattack which is
far from elementary
(to avoid it, White could play 5. Bxf7+ gaining a pawn).
If White ever loses a tempo with Nxh8 then the game is
hopelessly lost when Black plays perfectly!
I'm using this as an example of how a written analysis can be presented:
We show the strongest move of the winning side (Black here)
for every possible reply of the opponent,
except when the move to be refuted (Nxh8) is played.
The paradoxical consequence of the following refutation of Nxh8
is that the threat on the rook is only apparent.
At least for extremely sharp play...
Conveniently, the quoted 1967 game doesn't last very long because
of the mistakes of White (starting with 6. Kxf2).
The opponent of Traxler in 1890 didn't take the bait, which opens
up an interesting 17-move game.
Both actual games are shown in bold,
within the combined decision tree.
The term Traxler counterattack is normally used to describe this opening
(especially when the Bishop's sacrifice is accepted,
as in Traxler's original game 6. Kxf2).
However, in the United States, it's also called the Wilkes-Barre Variation
(especially when 6. Ke2 or 6. Kf1 is played)
because it was analyzed by
John Menovsky (1873-1947)
and other members of the
Wilkes-Barre Chess Club
(first established in 1887 and restarted in 1907).
Menovsky published the work in 1934 and 1935 and subsequently
discussed the problem with Kenneth F. Williams (1907-1993)
who would eventually publish a 58-page pamphlet on the topic in 1979,
with only few flaws.
Ken Williams (1907-1993) was once President of the
Correspondence Chess League of America (which was created in 1909).
His business commitments did not allow him to pursue an over-the-board tournament career which
essentially ended with a tie in a competition for the North-American Championship.
He went almost twenty years without playing a single over-the-board game.
Even with the best reply 6. Kf1 White lost all the games on record:
1947: James L Harkins vs. Eugene Levin (20 moves).
Arguably, the most famost miniatures of all time
was played informally on 21 June 1851, during a recess of the
first
international chess ournament, between
Adolf Anderssen (1818-1879) and
Lionel Kieseritzky (1806-1853).
Anderssen, playing White, sacrificed his queen, two rooks and a bishop to deliver
a brilliant mate with the three remaining minor pieces (without capturing a single black piece).
Short Chess Games by
Serguei Vorojtsov: |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
(2010-01-29) Sam Loyd's Chess Puzzles
Toying with chess positions which can't arise in actual games.
The American columnist Sam Loyd
(1841-1911) devised many clever puzzles based on the rules of chess
which have no relevance to actual play.
Lone black king on h4
(against 16 white pieces). Mate in 3 moves.
The same problem for other positions for the black king is less easy to analyze.
Tabulated below are the number of moves needed to mate, according to
Fritz 8.
In this context, e4 is almost always the strongest move;
often the only strongest move,
as indicated by the exclamation mark (!)... d4 is second best.
Full White Starting Lineup against Lone Black King
(2022-03-17) The
Botte de Nevers
of Chess (Maja's botte).
Pull-and-fork (attraction sacrifice). A startling 3-move combination.
This appears in about 2% or 3% of Chess Tempo tactical puzzles.
A sacrificial piece moves next to the king (usually grabbing something in the process, but not always).
As the king takes the bait, it's then forked with the true target.
The king may be forced to takes the bait but it may not be. In the latter case,
when the rest of the botte would result in an exchange of equal pieces,
the opponent choice is irrelevant to the puzzle, which may thus be truncated at that point
(as illustrated by
#73015808.
#48729,
#51993
or
#55364,
taken from a game resigned after the botte started with 2.Rxe7)
Examples (in order of ratings, at the time of writing):
Finally, #163607
is a borderline case of a passive botte, if we may call it that, where the rook to be sacrificed is already in place,
calling for a Swischenzug capture of a bishop.
Not covered here are pulls of pieces besides the king or the target
(e.g., a pawn getting the queen which grabbed the knight in
#163052)
or the rarer push-and-fork trick illustrated by
#62490
or the nice
#123150068
(where both possible replies to 1,Rg8+ allow the fork 2.NXC5+ which wins the rook).
I named this after the first person (Maja) with whom I shared (2022-03-17) my observation that the thing
is so prevalent in tactical puzzles (maybe, 2% or 3% of them). She gives medical advice about weight loss
and I mentioned my related quantifiable experiment with rated tactical puzzles as a test-tube for addiction.
She then revealed that she once competed in Chess at the national level in France...
As the dinner we were attending was drawing to a close, the dual-topic discussion was cut short (for now).
(2018-08-09) Elo Rating System
Rating player skills in a zero-sum game.
One key aspect of the Elo rating system is that the rating only change
as the outcome of a game but the sum of the ratings always stays the same.
Whatever one gains, the other loses.
An often overlooked consequence of this, is that the average rating of a fixed
pool of players never changes.
That average may only vary as new players enter the pool or old players
leave it as they retire or die.
To prevent the average rating from varying over time.
the regulator (e.g., FIDE in the case of Chess)
should estimate as accurately as possible the average of departing players
and attribute that average as the starting rating of new players.
Otherwise, the average rating changes over time not because
players are getting better or worse but simply because
the regulations for the starting ratingd of newcomers drive it lower or higher.
Nothing else.
On chess.com when you sign up, they ask you if you are
a beginner, intermediate, advanced or expert and just ask you an initial rating
of 1200, 1400. 1600 or 1800 accordingly.
The initial puzzle rating of everybody is 1000.
On Lichess, the initial puzzle rating of everyone is 1500.
In the case of Chess. we can also hudge the ski;; from games of record
and adjust the entry regulation to make the rating match the absolute skill so
obtained.
Comparing ratings from different eras :
Actual Elo evaluations allow the average of top players to drift substantially
over time and the individual ratings are subject to considerable uncertainty.
The skills of individual players throughout history is best estimated by
analyzing a significant sample of the individual moves they actually played
in the midgame without significant time constraints.
The opening moves should not be examined, as those depend greatly on current
fashion and/or collective encyclopedic knowledge which evolves over time.
Bobby Fisher tried to eliminate that by introducing what's now called
Chess960,
where the starting position is randomized among 960 possibilities.
One weakness of this approach is that the current chess engines
outplay the best human players using an artificial style which is
a poor predictor of typical human opposition on a move-by-move basis.
Yet, the results so obtained are equally flawed throughout
history and give an objective evaluation of actual skills which
strongly correlates with performance in actual matches between humans.
Computerization also allows private estimates of the Elo rating of players
who don't participate in regular chess tournaments with FIDE-rated players.
(2018-08-09) Chess Titles
FIDE titles for over-the-board regular chess play.
Historically, the title of Chess Grandmaster was first formally conferred by
Tsar Nicolas II
upon the five finalists of the
Saint-Petersburg tournament of 1914.
Namely:
José Raúl Capablanca,
Emmanuel Lasker,
Siegbert Tarrasch
Alexandre Alekhine,
and Frank James Marshall.
When the title was instated by FIDE in 1950, it was bestowed upon an initial list of
27
outstanding players still alive.
Complex rules are now in place, using
tournament norms and a minimum Elo rating for the award of this
top chess distinction and a few lesser titles,
as summarized in the following table:
Elo rating can be achieved anytime before tournament requirements, if any.
Between 1977 and 2003, FIDE awarded 31
Honorary Grandmaster titles to chess players with
outstanding records, including Jonathan Penrose (brother of
Roger Penrose) in 1993.
The courtesy couldn't be extended to
Rashid Nezhmetdinov (1912-1974)
who was already dead by then.
Since 2007, no formal distinction is made between these and other Grandmasters.
The Grandmaster distinction was awarded shortly after his death to
Karoly Honfi (1930-1996)
by the FIDE Congress of September 1996, in Yerevan.
In the Renaissance, the leading chess players listed below
were rarely challenged over-the-board in anything resembling a modern tournament.
The reputation of a chess player was often based on the success of the books he wrote.
The list below starts with Vicent, who is credited for
inventing modern chess, by increasing the power
of the bishop and the queen (replacing the lowly fierca
of shatranj). The earliest game of modern chess ever recorded,
in the form of a poem, was
Scachs d'amor (1475)
at a time when castling and en passant capture were
probably not yet standard. The first treatise was written by Vicent in 1493.
Last column indicates main residence during peak years.
For a whole century after the death of Greco,
The Calabrese (Le Calabrais)
the historical record doesn't single out any dominant player,
with the possible exception of Salvio from 1634 to 1640 who may have regained the
crown he had held before Greco.
Meanwhile, the nevralgic center
of World-class chess migrated from Naples to Paris...
Diderot and
Rousseaureported that the
the undisputed World center of chess in the mid-eighteenth century was the
Café
de la Régence in Paris.
Around 1730, François Antoine de Légal, sire de Kermeur
emerged as the most respected player there. (He spelled his own name Legall.)
Legall's only extant recorded game is the fabulous 7-move checkmate below,
known far and wide as Legall's mate.
Legall played this in 1750,
against Saint-Brié (Black)
at rook odds
(no rook on a1; a-pawn moved to a3).
Légal mentored the young Philidor who dethroned him in 1755 and famously
held on to the crown for 40 years, till his own death in 1795.
Philidor left Paris during the French Revolution and took on residence
at Parsloe's Coffee House on St. James Street
(that chess club was active from 1772 to 1825).
He was soon joined there by Verdoni, the strongest player in Europe
after Philidor (according to Philidor himself).
Arguably, Verdoni was the strongest chess player in the World
between Philidor's death (1795) and his own (1804).
Verdoni had learned chess at a mature age but was clearly superior to the other three leading
players he left behind in Paris (Bernard, Carlier, Léger).
Verdoni died in London on 25 January 1804
(in his Panton Street apartment). His first name and date-of-birth are unknown.
He left his position as Professor of Chess in Parsloe's club to
his star student
Jacob Henry Sarratt (1772-1819).
The London Chess Club was organized on the 6th of April 1807.
Chronologically, it was the third club created in London
(after Slaughter's in 1715 and Parsloe's in 1772).
None of those had yet gained enough momentum to compete with the
Café de la Régence.
So, after the passing of Philidor and Verdoni,
the crown went back to France.
The three leading players between 1804 and the arrival of Deschapelles (1815)
were Bernard, Carlier and Léger (in no particular order).
Tabulated below are the successive purported modern World champions rooted
in that era, with a few challengers of note (shaded rows).
Last column indicates main residence during championship years.
In the above table, yellow highlighting
is for the 17 people who have been undisputed World champions at some
point after the Steinitz era.
Two of them (Kasparov and Kramnik) held the
PCA/Braingames title at the dates indicated in red during the period (1993-2006)
when that title what distinct from the FIDE title.
Dates in black correspond to the World title recognized by FIDE.
The two titles were reunited in 2006 when Kramnik held them both. He was then heralded as the
14th modern World Chess Champion.
