The GBR code (or Guy–Blandford–Roycroft code) is a system of representing the position of

chess pieces A chess piece, or chessman, is a game piece that is placed on a chessboard to play the game of chess. It can be either white or black, and it can be one of six types: king, queen, rook, bishop, knight, or pawn. Chess sets generally come with si ...

on a

chessboard A chessboard is a used to play chess. It consists of 64 squares, 8 rows by 8 columns, on which the chess pieces are placed. It is square in shape and uses two colours of squares, one light and one dark, in a chequered pattern. During play, the bo ...

. Publications such as '' EG'' use it to classify

endgame Endgame, Endgames, End Game, End Games, or similar variations may refer to: Film * ''The End of the Game'' (1919 film) * ''The End of the Game'' (1975 film), short documentary U.S. film * ''Endgame'' (1983 film), 1983 Italian post-apocalyptic f ...

types and to index

endgame studies In the game of chess, an endgame study, or just study, is a composed position—that is, one that has been made up rather than played in an actual game—presented as a sort of puzzle, in which the aim of the solver is to find the essentially uniqu ...

. The code is named after Richard Guy,

Hugh Blandford Hugh Francis Blandford (24 January 1917 – 20 September 1981) was a chess endgame composer born in Southampton, England. Biography He spent several years of his childhood in Jamaica with his father, the Reverend Albert Francis (Frank) Blandford ...

and

John Roycroft Arthur John Roycroft (born 25 July 1929, London) is an English chess endgame study composer and author. Chess career In 1959 he was awarded the title International Judge of Chess Compositions. In 1965 he founded '' EG'', the first long-running j ...

. The first two devised the original system (the ''Guy–Blandford code'') using different figures to represent the number of pieces. Roycroft suggested to count one for a white piece and three for a black piece in order to make the code easier to memorise.

Definition

In the GBR code, every chess position is represented by six digits, in the following format: :abcd.ef * a =

queens Queens is a borough of New York City, coextensive with Queens County, in the U.S. state of New York. Located on Long Island, it is the largest New York City borough by area. It is bordered by the borough of Brooklyn at the western tip of Long ...

* b =

rooks Rook (''Corvus frugilegus'') is a bird of the corvid family. Rook or rooks may also refer to: Games *Rook (chess), a piece in chess *Rook (card game), a trick-taking card game Military *Sukhoi Su-25 or Rook, a close air support aircraft * USS ...

* c =

bishops A bishop is an ordained clergy member who is entrusted with a position of authority and oversight in a religious institution. In Christianity, bishops are normally responsible for the governance of dioceses. The role or office of bishop is ca ...

* d =

knights A knight is a person granted an honorary title of knighthood by a head of state (including the Pope) or representative for service to the monarch, the Christian denomination, church or the country, especially in a military capacity. Knighthood ...

* e = white pawns * f = black pawns For the first four digits, each of the first two white pieces counts as 1, and each of the first two black pieces counts as 3. Thus, for example, if White has two knights and Black has one knight, numeral ''d'' = 1 + 1 + 3 = 5. If that is all the other than the kings, the position is classified 0005. Values 0 through 8 represent all normal permutations of force. 9 is used if either side has three or more pieces of the same non-pawn type; these positions are possible in standard chess due to

pawn promotion In chess, promotion is the replacement of a pawn with a new piece when the pawn is moved to its last . The player replaces the pawn immediately with a queen, rook, bishop, or knight of the same . The new piece does not have to be a previously ca ...

. The last two digits of the code represent the number of white and black pawns, respectively.

Usage

GBR code can be used to refer to a general class of material. For example, the endgame of two knights against pawn (as famously analysed by A.A. Troitsky, leading to his discovery of the Troitsky line), is GBR class 0002.01. When indexing or referring to specific positions, rather than generalised material imbalances, the code may be extended in various ways. Two common ones are to prefix "+" to indicate the stipulation "White to play and win" or "=" for "White to play and draw"; and to suffix the position of the white and black kings. With these additions, the position to the right, a draw study by

Leonid Kubbel Leonid Ivanovich Kubbel (russian: Леонид Иванович Куббель; 1891 or 1892 – 1942) was a Russian composer of chess endgame studies and problems. Life He was born in Saint Petersburg at the end of 1891, or beginning of 1892 ...

(First Prize, '' Shakhmaty'', 1925), is classified as =0323.12g3g1. (The solution is: 1.Bf2+ Kh1 2.h7 c2+ 3.Be3 Rxe3+ 4.Kf2 Rh3 5.Bd5+ cxd5 6.hxg8=Q Rh2+ 7.Kf3 c1=Q 8.Qg2+ Rxg2.) The positions of other pieces can also be added; this produces a notation that provides the same information as

Forsyth–Edwards Notation Forsyth–Edwards Notation (FEN) is a standard notation for describing a particular board position of a chess game. The purpose of FEN is to provide all the necessary information to restart a game from a particular position. FEN is based on a sys ...

Examples of GBR code

References

* * {{citation , last= Roycroft , first=A. J. , authorlink=John Roycroft , title=Test Tube Chess , publisher=Stackpole , year=1972 , page=353 , isbn=0-8117-1734-8 Chess notation Chess endgames