Crazyhouse is June's Recognized Chess Variant of the month. Play it against your computer with Zillions of Games or play it online with Game Courier.

For two Camels, two Knights or a Wildebeest we can prove that the longest
forced mate is one move, because the geometry allows only a few mating
patterns. This two-move example with two cannons is not trivial. Is it
possible to prove that two moves is the maximum. Known is that the mating
patterns is always with the Black King on the side (X1), White's King on
X3 or on b3 against when X = a. And White's cannons are at Y1 and Z1 with
Y between X and Z and Y not adjacent to Z. The last move is a vertical move
by a cannon (C YA-Y1 or C ZA-Z1). Blacks last move is a horizontal King
move, which can only be forced if the end file is involved (Second rank
squares can only be covered by the White King), so this must be Ka1-b1,
which means that X = b. One retromove by a cannon later, c1 must be
covered. This is impossible. With two (Cannon + passive Bishop)-pieces
(passive Bishop is a Bishop that does not capture), it should work (from:
White CmB on c4 and c5, White King King b3, Black King b1, Black to move)
1. ...,Kb1-a1 2. CmB c4-f1, Ka1-b1 3. CmB c5-g1#. Probably (not certainly,
it should be possible to force this with two CmB's and a King against a
lone King.

It would be interesting to prove this (and of course the
King+Cannon+Knight against King)

The movement of the Cannon is one of three significant differences between
Xiangqi (Chinese Chess) and Changgi (Korean Chess) [the other differences
concern the Elephant and the design of the board - Changgi has no river).

The Koreans have somewhat simplified the movement of the Cannon.  Unlike
its Chinese cousin, the Korean cannon moves as it captures : it cannot
move at all without flying over a 'screen' piece.

The effect of all this is that the Korean cannon tends to be an immensely
powerful piece in the early and mid-stages of the game, equal or superior
to the CHA (rook), but practically useless in the endgame, when there are
few pieces left to leap over.  Part of the strategy of Changgi is knowing
just when to exchange the Cannon for another piece.

Another distinctively Korean feature of the Cannon is that, unlike its
Chinese counterpart, it cannot capture an enemy cannon, or leap over a
fellow-cannon, friend or foe.  Shades of blood brothers?