Bennekom Double Move Chess

Modifying Orthodox Chess to allow each player to make two moves per turn is an old idea, dating back to at least 1925 when a description of Marseillais Chess, probably the most common double-move variant, was published in local Marseillais newspaper Le Soleil. Another similar variant, Doublemove Chess, is also popular.

At an evening in December 1996, celebrating the 50th anniversary of the chess club of Bennekom, a village in the Netherlands, another double-move variant was being played. This variant is not mentioned in Pritchard's Encyclopedia of Chess Variants, and, not finding any occurence of it being mentioned anywhere else, Hans Bodlaender took the liberty of naming it Bennekom Double Move Chess. It might have been an invention of one of the organizers of this particular evening event.

Rules

The game is played as orthodox chess, but now each turn a player makes two moves with the same piece. The restriction that both moves must be made by the same piece is the primary difference which separates this game from other double-move variants.

Each move a player moves a piece, and whenever possible, he must then make another move with the same piece. When such a second move with this piece is not possible, the second part of the turn is skipped. For example, in this position, white can move his pawn from a2 to a3, which will force the end of his turn because no second move with that pawn is possible:

The only other exception is when a player's first move gives check. This will also end the player's turn with only one move. This prevents a player being able to actually capture the enemy king with a second move which would break a fundamental principal of orthodox chess.

If a player is in check at the start of a turn, he must get out of check immediately with the first move.

It is possible to capture two pieces in the same turn.

This concludes what we know for certain about how the Bennekom Chess Club played this game in 1996 but some open questions remain. It is probably safe to assume that all the typical rules of chess are unmodified wherever possible, such as the 3-fold repetition rule and the 50-move rule. The handling of the En Passant rule, however, is less obvious. It is probably best to rule that a player may only capture En Passant when the opponent has made the 2-space pawn move as his first, and therefore only, move. Otherwise, it would be the case that the pawn was already beyond where it could be captured by the opposing pawn, possibly even capturing another piece, since the two-space move. Allowing En Passant at that point would feel very unnatural from a chess perspective, especially if another piece has been captured. (Would that piece now come back, since the pawn was captured "in passing" before it reached this piece?)

Another open question is how white's first move of the game should be handled. Other popular double-move variants only give white a single move on the first turn of the game because this has the effect of cancelling out white's first-move advantage, thereby improving the game. Marseillais Chess originally allowed two moves at the beginning of the game but later evolved into "Balanced Marseillais Chess" wherein white began the game with only a single move. This modified version replaced the original version to such an extent that "Balanced" was almost universally dropped from the title, and now "Marseillais Chess" should be assumed to refer to the balanced version unless mentioned otherwise. Newer double-move inventions such as Doublemove Chess were created in a balanced form to begin with. Given that Doublemove Chess dates back to at least 1957, it is reasonable to assume that Bennekom should be "balanced" as well.