International draughts

International draughts (also called polish draughts or international checkers) is a board game, one of the variants of draughts. It is played on a 10x10 board with alternatingly dark and light squares, of which only the 50 dark ones are used. There are two players on 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.

Ordinary pieces move diagonally forwards one square and may jump (diagonally, two squares) multiple times over opposing pieces in a single turn forwards or backwards, after which the jumped over pieces are removed from the board. It is compulsory to jump over as many pieces as possible. A piece is crowned if it stops on the far edge of the board at the end of its turn (i.e., not if it reaches the edge but must then jump another piece backwards). Crowned pieces can move freely multiple steps along diagonals in any direction and may capture a piece some distance away and choose where to stop afterwards, but must still capture the maximum number of pieces possible. A player with no valid move remaining (typically with no pieces left) loses.

The game is popular in the Netherlands where it is known as dammen, and in other places. The World Draughts federation maintains a ranking, which as of 01 january 2003 is headed by Alexei Chizhov with the former champion Ton Sijbrands in second place.