PIECE PROMOTION CHESS (PPC)

Piece Promotion Chess is characterized by explosive attacking possibilities, hairtrigger struggles for survival, and few draws. Yet it has as much strategic profundity as chess itself and a wider variety of positions. With no opening or endgame theory, abundant mating possibilities even with limited material, and a whisker-thin margin between victory and defeat, it's like playing chess with no safety net and a souped-up engine. Punishment is swift... Yet the difference between PPC and Chess is very simple, seemingly rather slight:

1. Each player's back three ranks are his or her territory. The two middle ranks are neutral. Rooks, Knights, and Bishops promote upon reaching enemy territory. When a piece promotes, it does not become a Queen. Rather, it keeps its existing move, gaining the additional ability to move to any adjacent square. A promoted piece is called a Rooking (R'), Kniking (N'), or Bicking (N'), respectively, because it combines its original move with the move of a King (but without the King's restrictions: a promoted piece can move into attack and be captured). Oh, and it's Bicking because "Bishoking" would be too much of a mouthful.
2. A Pawn promotes on the eighth rank as in chess, but it must promote to either a Queen or a Kniking. There would be no advantage to any other promotion, because...well, see the next rule!
3. Just as in chess, the King can't be left in check and is never captured. But the object of the game is to leave the enemy King with no way to avoid capture on the next move. Therefore, delivering either checkmate or stalemate wins. (Consider stalemate "mate by zugzwang.") This cuts down on draws without compromising the principle that you have to get the King to win, and is actually more logically consistent than the chess rule.
4. To further cut down on draws -- cheap perpetual checks in particular -- it's illegal to play a check that repeats the position from two moves before (unless there are no other legal moves). Draws by repetition, including perpetual checks, are allowed if they avoid such Illegal Repeated Checks (IRCs). (In a perpetual check, there would have to be at least three moves between repetitions.) It is the player who delivers the check whose move is illegal and must be taken back.

Black to play and mate in two moves.
Upside-down pieces are promoted.
Can you see the solution?

Take a look at the game this position comes from

ZILLIONS OF GAMES implementation Note that the Zillions version does NOT implement rule #4 above -- unfortunately, it's just too complicated to make it work. Even if I could force Zillions to play by the IRC rule, I'm pretty sure it would slow it down and make it play quite a bit worse. I am sick of the Zillions langauge and don't want to futz with it any more. However, apart from that I did a really good job on it! It's fast, it understands the material values of PPC, it knows to develop its pieces and castle, and it even (inconsistently) realizes it should push passed pawns. Okay, it ain't Rybka-PPC, but its ability to calculate numerous mating lines almost instantly should make the 1 minute or higher speeds quite tough to beat for most (on my single CPU, 1.8 gHz dinosaur...if you have a fast computer, even the 30 second mode may be quite strong). That said, if you have the paid-for version of Zillions, download the zip file forthwith! (It's less than 20K.) Put "BWChess8x8.bmp" into Zillions Development\Zillions Demo\Images\Chess and "Piece Promotion Chess.zrf" into Zillions Development\Zillions Demo\Rules. That's it, you're done! Double-click on "Piece Promotion Chess.zrf" to play, or go into the Zillions program, control-R and select it. Here's something to try when you don't feel like playing yourself. In Zillions' Computer Opponent settings (under the Play menu), set the computer's thinking time to 10-15 seconds, with variety set at maximum, and let the computer play against itself. Wow, you'll get some really wild games! (Albeit not, I fear, extremely accurately played.) Try playing the first couple moves or so for both sides to get some opening variety. The difference from chess is quite obvious. PPC, in normal openings, is like chess in the King's Gambit. The PPC King's Gambit? A barrelful of monkeys doesn't even compare!

EQUIPMENT: The easiest way to play PPC on a physical board is to use two sets of pieces of substantially differing sizes. At the beginning of the game, use the Kings and Queens from the big set, all the other pieces from the small set. When a piece is promoted, replace it with a large piece of the same kind, signifying a Rooking, Kniking, or Bicking. The little pieces (Rooks, Knights, Bishops, and Pawns) are promotable; the big pieces (Kings, Queens, Rookings, Knikings, and Bickings) are nonpromotable and can move to any adjacent square.

On a computer screen, a promoted piece is just an upside-down version of the piece it promoted from.

NOTE: Piece Promotion Chess is not to be confused with the "Piece Promotion Games" created by Christine Bagley-Jones, or with Doug Chatham's "Bachelor Chess." Other than the fact that pieces promote, it has no real similarity to these games. PPC has a little more in common with PromoChess by Glenn Overby, or indeed with Shogi. The game it most closely resembles, however, is orthodox chess.

PPC is for those who love chess but are open to trying something different -- with a vicious combinatorial edge. PPC is more satisfying than variants like Gothic Chess where the possibilities for strategic play are overwhelmed by tactical firefights in the first few moves and minor pieces are relatively unimportant. PPC plays much like orthodox chess in the earlier stages of the game. Minor pieces are actually stronger than in the standard game. Yet when pieces come off the board, the position, instead of cooling off, tends to heat up to a desperate frenzy. Trade Queens and mating attacks may start building a few moves later.