Draughts on a 10x11 or 8x9 board.

[orac81]

I have been experimenting with draughts on a 10x11 board (international) or 8x9 board (checkers), using my programs Dynamo and Sage, which can play these setups.

This means an odd length, so that the Double corners are on the same side of the board. For Checkers, I think this has the effect that 3 kings do not beat 2 kings, if the 2 kings are in both double corners, which is not true for 8x8.

What effect would a 10x11 board have on International draughts? I have played Dynamo with this, but I am not sure of the implications. I know the long single corner diagonal is important in 10x10, that is now lost in this variant.

Git: https://github.com/orac81/Orac-Draughts

[Rein Halbersma]

I have been experimenting with draughts on a 10x11 board (international) or 8x9 board (checkers), using my programs Dynamo and Sage, which can play these setups.

This means an odd length, so that the Double corners are on the same side of the board. For Checkers, I think this has the effect that 3 kings do not beat 2 kings, if the 2 kings are in both double corners, which is not true for 8x8.

What effect would a 10x11 board have on International draughts? I have played Dynamo with this, but I am not sure of the implications. I know the long single corner diagonal is important in 10x10, that is now lost in this variant.

Git: https://github.com/orac81/Orac-Draughts

On N x (N-1), N x (N-2), and N x (2 N - 1) boards 3 kings beat 1 king in international draughts. So 8x6, 8x7, 8x9, 8x10, 10x9, 10x11, 10x12, 8x15 and 10x19 are all special.

[Rein Halbersma]

I have been experimenting with draughts on a 10x11 board (international) or 8x9 board (checkers), using my programs Dynamo and Sage, which can play these setups.

This means an odd length, so that the Double corners are on the same side of the board. For Checkers, I think this has the effect that 3 kings do not beat 2 kings, if the 2 kings are in both double corners, which is not true for 8x8.

What effect would a 10x11 board have on International draughts? I have played Dynamo with this, but I am not sure of the implications. I know the long single corner diagonal is important in 10x10, that is now lost in this variant.

Git: https://github.com/orac81/Orac-Draughts

Btw, on a 4x4 board 2 kings also don’t beat 1 king in checkers!
Did you generate endgames databases to verify the 3 vs 2 kings in checkers?

There is a Dutch draughts book called “3 tegen 1 is gemeen” which is about this endgame on all kinds of exotic boards.