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This page is written by the game's inventor, Ralph Betza.

Trap Chess

Yesterday I played a game of 5-minute Chess in the park:
1 e4 e5 2 Bc4 Nf6 3 Nc3 Ne4 4 Bf7 Kf7 5 Qh5 Kg8 6 Ne4 d5 7 Ng5 Qf6 8 d3 g6 9 Qf3 Qf3 10 Ng1f3 Bg7 11 Bd2 h6 12 Nh3 g5 13 Nhg1 e4

Although trapping pieces is something I do quite often, I have rarely seen (or done) anything as elegant as this; and after some uninteresting moves, the game ended with a W Rook being trapped as well.

Naturally, I thought about designing a chess variant to commemmorate this game. What would Trap Chess be? Hmmm...

The Rules of Trap Chess

You can't make a capture unless the piece is trapped. For example, after 1 Nc3 Nf6 2 Ne4, no captures can be made, and there is a threat of Ne4-d6 checkmate.

Check is pictorial, so in our example if 2...d7-d5 3 Ne4-d6+, it is check even though the K could not be captured (it can run away, so it's safe from capture; but it's check anyway because "it looks like check").

Finally, let's make sure we understand "trapped": if a piece has any legal move that can bring it to a square that is not attacked, it is not trapped. If the piece has no escape that is both safe and legal, it is trapped.

For example 1 e3 e5 2 Nf3 Be7 3 Ng5 Bf6 4 Bc4 h6 5 Qf3 (capturing on f7 would be stronger) e4 5 h3, and now 5...h6:g5 is legal because the escape Ng5:e4 is safe but not legal and the escape Ng5:f7 is legal but not safe -- the Ke8 attacks f7 even though it can't really capture there.

Is it Playable?

This is a nice idea, and it might even be a playable game.

Obviously, a pinned piece is trapped; and a Pawn attacked vertically by a R or Q is trapped. Does this give W a blowout fast win?

Warning: I've had a lot of trouble doing this analysis. It's easy to make a mistake about whether a move is legal or not.

1 e4 e5?? 2 Qh5 does win at once. There is no defense against the combination of the threat of Qh5:f7 mate (legal because a pinned piece such as the Pf7 is always trapped), plus the threat of Qh5:h7:h8 (both this and the previous can be defended by ...g7-g6, but then the next threat gets stronger), plus the final threat of Qh1:e5+ and Qe5:e7 checkmate.

1 e4 d5? 2 Qg4 threatens both Qg4-d7 mate and Qg4:g7 which wins the R and more.

1 e4 e6 2 Qg4 Qg5 is a simple and safe defense? Remember that 3 Qg4:e6+ is illegal.

1 e4 e6 2 d4? Bb4+ wins for Black.

1 e4 e6 2 Qh5! g6 3 Qe5 (or Q:g6) Bg7 4 Qe6+ wins; or 1 e4 e6 2 Qh5! Qf6? 3 Qf7; or 2...Nf6 3 Qe5 (perhaps 3 Qd5 is even stronger!); or 2...Qg5 3 Qf7 (the Q is uncapturable because she has an escape square at f3).

Perhaps 1 e4 g6 is playable (hmmm, but what if 2 Bf1-b5), but I already don't like the way the game is shaping up, and so I'll add one more rule:

One More Rule

The royals are different. The King may capture pieces even though they are not trapped, and the Queen may be captured even when she is not trapped.

With this final rule, I believe the game is likely to be playable, but I still can't be sure.

What's It Like?

In Trap Chess, it is difficult to capture pieces, but it is easier to give check than it normally is. (It is easier to give check because the attacking piece is often uncapturable.)

Therefore, one expects the game to be explosive, featuring sudden tactical finishes in apparently calm positions.

Written by Ralph Betza.
WWW page created: June 22, 2001.