Checkers

Checkers board.

Checkers (or draughts) a group of board games which involve the "jumping" of enemy pieces.

Table of contents

1 History
2 Rules
3 Computer Players
4 Variants
5 Famous Checkers Players

History

The game of draughts is thought to have originated in around 1100 AD, probably in southern France. It is thought the inventor created this board game by using a Chessboard, with the rules of Alquerque.

The pieces were originally called "ferses", the name that was given to chess queens at the time, and the draught ferses moved in the same way as the queen did in chess. Note however at this time, the queen was able only to move one square per turn. The one new move this game introduced was the ability to jump over opponent's pieces and take them. At this time the game was known as "Fierges".

In Philip Mouskat's "Chronique" (1243) is a reference to the use of "Kings" suggesting that the ability to promote a piece existed at this time.

When in Chess "ferses" were renamed to "Dame", the same occurred in Draughts, the games name also changed to "Dames". While it is thought that the original Fierges had a compulsory capture rule, there is no evidence that this rule existed in Dames. This rule was however reintroduced in France in the year 1535. Modern play includes this rule.

The name "Checkers" originated with European settlers in the USA.

Rules

English Checkers (draughts) is played on an 8x8 chessboard, but only uses the dark squares.

The rules are:

Each player starts with 12 pieces on the three rows closest to himself. (See diagram above.)
Each turn, a player can move one of his pieces diagonally forward or jump diagonally forward over a series of enemy pieces, which are then removed from the board. Captures are mandatory, however, if different captures are possible, any of them can be chosen.
Multiple captures are possible, and if started must be completed.
When a piece reaches the opposite side, it becomes a king with the ability to move and jump diagonally backwards as well as forwards. A king is represented by two pieces of the same colour, one on top of the other.
A player who cannot make a move loses.

In tournament checkers, a variation called three-move restriction is preferred. The first three moves are drawn at random from a set of accepted openings. Two games are played with the chosen opening, each player having a turn at either side. This tends to reduce the number of draws and can make for more exciting matches. Three-move restriction has been played in the United States championship since 1934. A two-move restriction was used from 1900 until 1934 in the United States, and in Great Britain until the 1950s. Before 1900, championships were played without restriction: this style is called go-as-you-please.

Computer Players

The first computer player of checkers was written by Arthur Samuel, a researcher from IBM. Other than it being one of the most complicated game playing programs written at the time, it is also well known for being one of the first adaptive programs. It learned from its opponents and adjusted its strategy accordingly.

The strongest checkers player is a program called Chinook written by a team led by Jonathan Schaeffer. Marion Tinsley, world champion from 1955-1962 and 1975-1991, won a match against the machine in 1992. In 1994, he had to resign in the middle of an even match because of health reasons; he died shortly thereafter. Chinook was retired after winning the world man-machine champion title. Today's PC programs are stronger than the best humans. It is generally expected that checkers will be solved by 2010.

It is a common misconception that checkers has been solved. The best computers can now beat all humans, but checkers is not yet completely solved. However, the man-machine title is not as meaningful as it was 10-20 years ago, because most human experts are over 60 years old, as few/no young players have invested the effort to become experts.

The number of legal positions in checkers is estimated to be 10¹⁸, and it has a game-tree complexity of approximately 10³¹.

Variants

In Spanish/German/Russian checkers the kings can move as far as they want along any diagonal, like a bishop in chess; although, they cannot capture like a Bishop.
In international draughts (or international checkers), the board is 10x10 with 20 pieces each, and the kings move as far as they want on diagonals. This is popular in the Netherlands, France, some parts of Africa and some parts of the former USSR and other eastern European countries.
In Turkish checkers pieces move straight forwards or sideways, kings moving like a rook in chess, so that both red and black squares are used. Each player starts with 16 pieces in the first two rows.
In Halma pieces can move in any direction and jump over any other piece, friend or enemy. Each player starts with 19 (2-player) or 13 (4-player) pieces all in one corner and tries to move them all into the opposite corner.
Chinese Checkers is based on Halma, but uses a star-shaped board divided into triangles, and is played using marbles instead of chips.