Inspired by this comment, I decided to come up with a chess variant for RoboRally. I wanted to keep the programming aspect of RoboRally and the multiple pieces & capture-the-king goal of chess intact. Programming a “side” of 16 bots would be too daunting, but a king bot and a handful of piece bots (using chess pieces) would be manageable.
The chess pieces need to have easily identifiable facing, so pieces from Chess Teacher, chess dice from Proteus, standard chess pieces mounted on some teardrop-shaped bases, or gaming miniatures that are evoke the proper piece (clerics, mounted riders, perhaps golems for rooks, etc.) could be used. The king itself could be a standard RoboRally bot. Each player needs a king and a selection of pieces, for example, a rook, a bishop, and two knights.
Select one (or two) of the more symmetrically balanced boards from RoboRally—the “Chess” board from the Avalon Hill edition is an obvious choice, but there are many more that will work. You could use an empty grid as well, but then this becomes more chess and less RoboRally.
The two players set up their pieces on the two rows closest to opposite ends of the selected arena (secretly, if each wants to wait until the other sets up before deciding on their own set up). Deal out starting hands of 9 RoboRally cards.
Each turn, players lay out programs of five cards. The cards are revealed and executed in priority order. For each card, however, a player chooses any one of his pieces to move. A “Move 1″ allows a piece to make its normal chess move (and maintains the piece’s facing); all other cards would use their normal RoboRally movement or turning effect. Opposing robots landed on with a “Move 1″ chess move are captured; robots landed on with any other movement are pushed per the RoboRally rules. There are no checking rules as in chess, since the eventual capture requires hidden information (the presence of a “Move 1″). No castling or en passant captures either, for that matter.
Knights using a “Move 1″ are subject to effects similar to those of the “Frog Legs” option: the knight can pass over pits but would get stopped by walls; the knight move can be made only if a three-square path from the starting space the the landing space could be traversed by a flying robot.
A bishop can move through any vertex unless a wall or open pit on the bishop’s left and a wall or open pit on the bishop’s right meet at the vertex.
A piece ending a turn on a double-wrench space farthest from its starting edge can be promoted (instead of any healing damage or gaining an option). That is, of the rows that have any double-wrench spaces, only the row farthest from the starting edge row “empowers” its double-wrenches with promotion capability.
The object of the game is to capture the opposing king with a chess move or eliminate him through Robo Rally effects (pits, crushers, or accumulated damage). Only damage to the king reduces the number of cards drawn.
Shogi pieces could also be used this way (and have good facing). You could even mix-and-match shogi pieces, other regional chess-like games’ pieces, or fairy chess pieces (see Chess variants). If you get really deep into it, you can also experiment with unbalanced sides, piece drafts, or point buys—let me know how it goes!