1. Players play in teams of two against other pairs; White and Black play against Black and White.
rnbqkbnr RNBKQBNR
pppppppp PPPPPPPP
.+.+.+.+ .+.+.+.+
0 +.+.+.+. +.+.+.+. 0
0 .+.+.+.+ .+.+.+.+ 0
+.+.+.+. +.+.+.+.
PPPPPPPP pppppppp
RNBKQBNR rnbqkbnr
2. Captured pieces are passed to your partner straight away; the pieces you receive will be the same colour as your pieces on your board.
3. Instead of making a move on your board, you can 'drop' any captured piece onto any vacant square, except that pawns may not be dropped onto the first or the eighth rank. Pieces can be held 'in hand' behind your first rank and must not be hidden from your opponent.
4. Pieces can be dropped to give check.
5. A piece can be dropped to give checkmate.
6. Mate on either board ends the game.
7. Flag fall on either board ends the game.
8. 12 minutes are allowed for each player for the game. Clocks (00) should be placed at each end so that all four players can see the time on both clocks.
9. Players can advise partners about pieces they would find useful. Please try to do this with minimum, and not maximum, volume.
10. Touch move and touch take do not apply; pressing the clock completes a move.
11. The decision of the arbiter, however unfair, is final.
Example game:
https://en.wikipedia.org/wiki/Bughouse_chess#Notation_and_sample_game
Black wins on the left-hand board by dropping a Queen with check onto d2; the Queen must be taken by the Bishop, then the original Black Queen comes down to give mate.
Grateful thanks are offered to Berkshire Junior Chess Association for a peek at their rules.