Ambar Chatterjee
Engine Forbidden Tournaments

In AICCF server, when a game reaches a position which is tabulated in the Endgame Tablebase, the game is stopped for Adjudication. The game is then scored as win/draw/loss by the AICCF maintainer after checking the position at the Tablebase website.

In the previous Bulletin we wrote that access to 7-men endgame tablebases is not free. For this reason we had limited the AICCF server to 6-men tablebases only. However Austin Lockwood (ICCF Services Director), pointed out that this is no longer the case. LiChess offers the complete 7-men endgame tablebase entirely free of cost.

Accordingly, from 22nd December 2019, we implemented 7-men endgame tablebases on AICCF server (and also the AA Server). Subsequently, ICCF has also implemented 7-men endgame tablebases from 01-Jan-2020.

Players need to be aware about the difference between endgame tablebase implementation on AICCF and ICCF server. In AICCF server as soon as a game reaches a position with only 7-men remaining (counting pieces and pawns from both sides) the game is stopped. In your games list you will see that you can no longer make any moves and the game is marked for Adjudication. The AICCF server maintainer periodically looks for games that have been stopped and checks the position in the 7-men Tablebase website ( and sets the result. No action is required by the players. But on the ICCF server, a player must himself notice that there are only 7 men (or less) left and make a claim of win or draw. The claim can only be made when it is the player's turn to move. ICCF server automatically checks the position in the Syzygy Tablebase and sets the result if the claim was valid.

The first game on AICCF Server to be scored with 7-men Tablebase Adjudication was N005: B.S. Dutt – S. Anpazhakan. In the position below, Black to move, there are 4 White men (K and 3 P) and 3 Black men (K, R, P) with a total of 7 men.

Black has a Rook but it will have to be given up White’s c-pawn which is about to Queen and after that White’s b-pawn will Queen. The tablebase ( shows a win for White. Hence this game was scored as a win for B.S. Dutt.

Discussion on AICCF WhatsApp group shows that most of members would like tablebase adjudication only for Engine-Allowed games and not for Engine-Forbidden games. The AICCF server is being updated shortly with this change. Players will be informed by email after the change is implemented.