A strong chess player and an expert on games in general, David Prichard four years ago brought out an extremely learned Encyclopaedia of Chess Variants, which he published himself and contains descriptions of some 1,450 chess strains.
His new work is, as the title suggests, much more popular in intent with quite detailed instructions on a mere 20 variants, the first 18 of which can be played with a standard chess set - the last two, which can't, are Chinese Chess and Shogi.
While I've encountered and played a few of these before, many of the others sparked only a very vague memory or were completely new. One of these was the mind-bending "Alice Chess" in which there are two boards side by side, with one starting from the normal initial position and the other empty. The rules are simple to state but confusing to follow:
1. A move must be legal on the board on which it is played.
2. The square to which the piece is moved must be vacant on the other board. 3. On completion of a move the piece is immediately transferred ("through the looking glass") to the corresponding square on the other board.
Pritchard gives several complete games but rather than stretch your - and my - ratiocinatory processes at this fragile time here is the Alice Chess equivalent of, as he says, "Fool's Mate": 1. e4 d5 2.Be2 dxe4 3.Bb5 mate! At the end, "board B" is empty and "board A" looks as though a normal game has been played but it's mate because any piece attempting to interpose would fly off to "board B".
A couple of weeks ago, I received a splendid CD-Rom called Zillions of Games, a "generic game-playing engine" that can play a whole gamut of different board games after being fed the rules in special script files. The CD, which costs $29.95 (plus $10 postage to the UK) is available from http://www.zillions-of-games.com and currently contains nearly 300 different games, though free upgrades are already available.
Among these are over 20 chess variants including Extinction Chess, in which the object is to wipe out any one of the opponent's six "species" - king (which can be taken), queen, rook, bishop, knight, pawn.
Here is a short sample game given by Pritchard and won by R.Schmittberger: 1.e4 e6 2.d4 d5 3.exd5 exd5 4.Qe2+ Be6 5.b3 Nc6 6.Nf3 Qf6 7.Bb2 0-0-0 8.Nbd2 Bg4 9.0-0-0? Bxf3! 10.gxf3? (10.Qe3! was forced) 10...Qf4 and White can't prevent either 11...Qxd2 or 11...Qxc1 so he resigned.