Rules Update: Tablebases in Correspondence Chess

Rules Update: Tablebases in Correspondence Chess

Sep 7, 2018, 9:33 AM |

Endgame tablebases have recently become an integral part of correspondence chess, to the extent that they are even used to adjudicate games in ≤6-piece positions in ICCF tournaments. It's been frequently expressed that such a tool should be allowed because it is a human-derived resource in the same vein as theoretical opening books. has decided to follow our members in embracing any-piece tablebases during all stages of your daily chess games. What this means is that during your own analyses, you will now be able follow a line all the way into a 6-piece position and check your tablebase to see if the position is winning, drawing or losing. is now working on setting up a new tablebase feature that can be accessed directly from analysis. For now, there are many online resources for you to look up a position, such as on k4it or chessok. I would recommend that you use those services instead of a tablebase connected to an engine which may lure you into accidentally accessing illegal engine analysis for a non-tablebase position.

Here may be as good a place as any to elaborate on some of the lesser-known rules of correspondence play:

  • You cannot receive help from another person in your daily games. Receiving advice from a tutor, friend or person over your shoulder is not allowed and may result in the closure of your account!
  • You cannot look at any pre-prepared engine evaluations you've compiled or written down. You may have put a lot of work into your opening theory with an engine, but to use those lines you will have to use just the moves themselves without the direct engine outputs.
  • You can access the analyses of human players in thematic games. If a popular game has been analyzed by a human player you may surely read their thoughts on the position as long as their analyses do not include engine evaluations.
  • With the legality of tablebases there is one best practice we'd like to introduce which is that despite the fact that tablebases are more accurate than engines, an engine should not be used to analyze positions with ≤7-piece positions. This is not exactly a rule, because we cannot enforce it, but we'd like you to separate engines from your correspondence play at all times.

For a full description of the rules of fairplay on you can head here:


Gerard Le-Marechal,
Head of Fairplay on