### The Game of Laskers, Other Checker Variations, and Links Regarding Mathematics and Chess

A checker game invented by Emanuel Lasker, Ph.D. offers a domain where a succession of visual patterns must be manipulated.

(Dr. Lasker is known in mathematics and philosophy. He studied under Hilbert and was awarded the Ph.D. in 1902. He became World Chess Champion 1894; held the World Chess Championship until 1921; and is considered by many to be the greatest chess player ever.)

In this game pieces are stacked. Here side indicates red or black, i.e., the two players. The game has an interesting nature: side-change can result from captures. This is so because a jumped checker isn't removed from the board as in the ordinary game. Instead a jumped stack of checkers often remains on the board because the jump only removes the top checker, which is carried off at the bottom of the jumping stack.

Each checker-stack-entity is a piece. Its motion is under the control of the side with the same color as the top checker. In any jump only the highest checker is carried off under the conqueror.

The top checker of a stack is flipped over when a piece reaches the eighth rank. This makes a crown show, and leads the piece under it to act like a king in ordinary checkers. In other words the piece can move backwards as well as forwards. That continues until it is jumped, causing the top checker to go with its conqueror.

All jumps are forced (an offered jump must be taken unless there is another jump available; double-jumps must be taken even if it would be advantageous to cease after a single jump). Ordinary-checker rules apply. A game ends when one side cannot move.

[Seeing the king/ordinary-distinction is easier if liquid white-out outlines each crown.]

In Lasca, Lasker describes a 7x7 board with 22 pieces that follows this system. That reference as HTML was transcribed by Peter Billam from a PDF scan of the original.

Also see Rules of 'Lasca' The Great Military Game and Wikipedia on Lasca.
Gardner, Martin, The Last Recreations, NY: Springer-Verlag Copernicus, 1997, has 26 pages of various checker items. One suggestion is shown as Diagonally. To play the usual form of checkers against a computer see Take Red.