International draughts starting position
Abstract strategy game
|Setup time||10–60 seconds|
|Skill(s) required||Strategy, tactics|
International draughts (also called Polish draughts or International checkers) is a strategy board game for two players, one of the variants of draughts. It is played on a 10×10 board with alternatingly dark and light squares, of which only the 50 dark squares are used. The two players are at opposite sides, with 20 pieces each, light for one player and dark for the other. In conventional diagrams the board is displayed with the light pieces at the bottom and dark at the top and in this orientation the lower-left corner square must be dark.
The World Draughts Federation maintains a ranking. As of October 2009[update] the men's list is headed by Ton Sijbrands from the Netherlands, followed by Alexander Georgiev from Russia and Alexander Schwarzman from Russia, while at the women's site Darya Tkachenko from the Ukraine is in the lead, closely followed by Tatjana Chub from the Netherlands and Zoja Golubeva from Latvia.
The general rule is that all moves and captures are made diagonally. All references to squares refer to the dark squares only. The main differences from English draughts are: the size of the board (10×10), pieces can also capture backward (not only forward), the long-range moving and capturing capability of kings, and the requirement that the maximum number of men be captured whenever a player has capturing options.
- The game is played on a board with 10×10 squares, alternatingly dark and light. The lower-leftmost square should be dark.
- Each player has 20 pieces. In the starting position (see illustration) the pieces are placed on the first four rows closest to the players. This leaves two central rows empty.
Moves and captures
- The player with the light pieces makes the first move. The two players make moves alternately.
- Ordinary pieces move forward one square diagonally to a square that is not occupied by another piece.
- Opposing pieces can and must be captured by jumping over the opposing piece, two squares. If one has the possibility to capture a piece then this must be done even if it is disadvantageous.
- If there is one unoccupied square before or behind opposing pieces then jumps multiple times over opposing pieces in a single turn forward or backward can and must be made, making angles of 90 degrees. It is compulsory to jump over as many pieces as possible. One must play with the piece that can make the maximum captures.
- After the piece has jumped over the opponent's piece or pieces, the jumped-over pieces are taken from the board. The men are not removed during the jumping move, only after the entire move is completed.
- The same piece may not be jumped over twice.
- A piece is crowned if it stops on the far edge of the board at the end of its turn (that is, not if it reaches the edge but must then jump another piece backward). Another piece is placed on top of it to mark it. Crowned pieces, sometimes called kings, can move freely multiple steps in any direction and may jump over and hence capture an opponent piece some distance away and choose where to stop afterwards, but must still capture the maximum number of pieces possible.
Winning and draws
- A player with no valid move remaining loses. This is the case if the player either has no pieces left or if a player's pieces are obstructed from making a legal move by the pieces of the opponent.
- A game is a draw if neither opponent has the possibility to win the game.
- The game is considered a draw when the same position repeats itself for the third time (not necessarily consecutive), with the same player having the move each time.
- A one king against one king endgame is automatically declared a draw, as is any other position proven to be a draw.
These are extra rules accommodated in some tournaments and may vary:
- If, during 25 moves, there were only king movements, without piece movements or jumps, the game is considered a draw.
- If there are only three kings, two kings and a piece, or a king and two pieces against a king, the game will be considered a draw after the two players have each played 16 turns.
Each of the fifty dark squares has a number (1 through 50). Number 46 is at the left corner seen from the player with the light pieces. Number 5 is at the left corner seen from the player with the dark pieces.
Computer draughts programs have been improving every year. Programmers wrote the first draughts programs in the mid 1970s. The first computer draughts tournament was in 1987. In 1993, computer draughts program Truus ranked about 40th in the world. In 2003 computer Draughts program Buggy beat world number 8 Samb. In 2005, the 10-time world champion and 2005 World champion, Alexei Chizhov, commented about computers. Chizhov said he could not beat the computer, but he also would not lose to the computer. In 2010, the 9 piece endgame database was built.
Schwarzman beat Maximus (2012)
Alexander Schwarzman beat computer program Maximus on April 14, 2012. Schwarzman won game 2 in the 6 game match. The other 5 games were draws. Schwarzman was world champion in 1998, 2007 and 2009. Jan-Jaap van Horssen of the Netherlands wrote Maximus. Maximus used a 6 piece endgame database. The computer was an Intel core i7-3930K at 3.2 GHz 32 gigabytes memory, a 6-core with hyperthreading. The average search depth was 24.5 ply. The average number of moves evaluated per second was 23,357,000. The average search time was 3 minutes and 52.98 seconds.  
List of top International draughts programs
- Oldest computer draughts program
- Oldest computer draughts tournament
- Searching for Solutions in Games and Artificial Intelligence By Louis Victor Allis. Chapter 6 section 3.8 page 169
- Computer beats the 8th strongest draughts player in 2003
- Draughts champion Alexei Chizhov talks about computers
- Gilbert, Ed. "9 piece endgame database". Retrieved 4 October 2011.
- "Maximus – Schwarzman: digitale gladiator tegen keizer van vlees en bloed" (in Dutch). Retrieved 10 May 2012.
- van Horssen, Jan-Jaap. "Maximus vs. Schwarzman draughts match". Draughts, Computer, Internet. World Draughts Forum. Retrieved 10 May 2012.
- Kingsrow Ed Gilbert site
- FMJD (World Draughts Federation) Rules and Regulations