The Rules of 4x16 Race Chess
The well-known 4x16 circular board is used, with the usual setup of pieces. The difference is that Pawns may only move clockwise.A new rule is that a Pawn can be promoted if it makes a full circle (more or less). White Pawns promote at the first rank, Black Pawns promote at the 9th rank.
After some experimentation, Joao Neto and I decided that the ASCII diagram for this game should be sideways, with some ranks repeated.
I still don't know why Joao likes to use an O instead of a P for White pawns, but I changed it here.
Sample Game
White: J. Neto (Fab. Fides) Black: R. Betza (Fab. Fides) a . . P R R P . . . . p r r p . . . . b . . P N N P . . . . p n n p . . . . c . . P B B P . . . . p b b p . . . . d . . P K Q P . . . . p k q p . . . . 1 1 1 1 1 1 1 1 1 5 6 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 1. b4-b5 d12-d13 2. c4-c5 c12-c13 3. Bc3-a5 Nb10-c12 4. Nb2-c4 d12-d13 5. c5-c6 d13-d14 a . . P R R P B . . . p r r p . . . . b . . P . N . P . . . p . n p . . . . c . . P B . N . P . . p b b n p . . . d . . P K Q P . . . . p k q . . p . . 1 1 1 1 1 1 1 1 1 5 6 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 6. b5-b6 Qd11-d13 7. b6-b7 a12-a13 8. b7-b8 a13-a14 9. Nc4-b6 a14-a15 10 Nb6-a8 Kd10-d11 11 Ba5-d8 d14-d15 a p . P R R P . . . N p r r . . . p . b . . P . N . . . . P p . n p . . . . c . . P B . . . P . . p b b n p . . . d p . P K Q P . . . B p . k . q . p . 1 1 1 1 1 1 1 1 1 5 6 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6Black appears to be behind in the race, because I have made two defensive moves (moving up the Queen so I could move up the King).
However, the defensive idea is that White can win the Pawn at c9 and occupy the square with a Pawn or with a Bishop, but then has no immediate followup. He won't be able to make any progress until he brings in some more attackers to pile up on b9 or d9, and in the meantime Black gets to advance his attack.
12 Kd2-c3 d15-d16 13 a4-a5 Ra11-a14 14 a5-a6 Nc12-b14 15 a6-a7 Nb14-d15 16 Ra3-a5 Nd15-b16 17 Ra2-a4 d16:c1 18 Na8:c9+ Nb11:c9 19 b8:c9 Ra14-d14 a p . P . . R R . P . p r . . . . p . b . n P . N . . . . . p . . p . . . n c . . p B K . . P . . P b b . p . . . d . . P . Q P . . . B p . k . q r . . 1 1 1 1 1 1 1 1 1 5 6 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6Black's Queen and Rook are stealthy in the ascii diagram, because it is not so easy to see that they attack the Pawn at d1.
In this position it is clear that Black is winning the race by a big margin. Instead of a4-a5-a6-a7, White might have tried 13. c6-c7, 14. c7-c8, and 15. Na8-c7, with a better attack; if Black's Knight then arrived at b16 and the Rook at a2 turned out to be trapped, it would be a worthwhile sacrifice of the Exchange.
In the diagram position, 20 Qd3-a6 Nb16:d1+ 21 Kc3-b4 would be worth a try.
20 d1-d2 c1:d2+ 21 Nb3:d2 Ra9-a14 22 d4-d5 Ra14-c14 a p . P . . R R . P . p . . . . . p . b . n P . . . . . . . p . . p . . . n c . . . B K . . P . . P b b . p r . . d . . . N Q . P . . B p . k . q r . . 1 1 1 1 1 1 1 1 1 5 6 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 23 Ra5-c5 a15-a16 24 Kc3-b2 Rd14:d2 25 Qd3-c3 Nb16-d12+25...a16:b1 is more logical, and there was no way to stop it.
This game demonstrates that race chess works exactly as designed. Attack and defense must be carefully balanced in order to win the race and checkmate the opponent before you get mated.
Collision Chess
An idea that has never been tried is "Collision Chess".It is similar to Race Chess: in Race Chess, all the Pawns move clockwise; in Collision Chess, all the White Pawns move clockwise, but all the Black Pawns move counterclockwise.
Here is 4x12 Collision Chess:
a r p P R N P . . . . p n r p P R
b q p P Q B P . . . . p b q p P Q
c k p P K B P . . . . p b k p P K
d r p P R N P . . . . p n r p P R
1 1 1 1 1
1 2 1 2 3 4 5 6 7 8 9 0 1 2 1 2
1. c4-c6 c9-c7 2. Nd3-c5 Nd10-c8 3. a4-45 a9-a8 4. Na3-c4 Na10-c9
5. b4-b6 b9-b7 6. d4-d5 d9-d8 7. Bb3-a4 Bb10-a9
a r p P R . B P . . p b . r p P R
b q p P Q . . . P p . . . q p P Q
c k p P K B N N P p n n b k p P K
d r p P R . . P . . p . . r p P R
1 1 1 1 1
1 2 1 2 3 4 5 6 7 8 9 0 1 2 1 2
As usual, a symmetrical defense is difficult for both players.
Making a Pawn capture allows the opponent to get the open Rook file,
but White's failure to capture can lead to his advantage being
dissipated. White seems to gain nothing with 8 a5-a6 c7:b6 9 a6:b7
b6:c4 10 b7:c8, and 8 a5-a6 c7:b6 9 Nc4:b6 Nc8:b6 10 Qb1:b6 Ba9-c7!?
also seems unprofitable.
Here is 3x13 Collision Chess:
a r p P R N B P . . p p n b r p P R
b p p P P K Q P . . . p q k p p P P
c r p P R B N P P . . p b n r p P R
1 1 1 1 1 1
2 3 1 2 3 4 5 6 7 8 9 0 1 2 3 1 2
This game has exactly 39 squares, and so it should be called "Jack
Benny Chess" in honor of the famous comedian who claimed to be 39
years old for 39 years in a row. You will notice that it uses a
complete standard chess set on a very small board.