Would you like to take it back? You can't save your cannon, but you will save yourself a move, which can be quite valuable.

If you choose not to take back, my move will be H-g5

As another observation, those cannons really strengthen this game which I otherwise find full of weaknesses, as I pointed out before. There are some fascinating tactical combinations that they can perform, and they really can exert a powerful influence from a distance.

Another thought: in chess, some brilliant moves by one player (or idiotic moves by the other) can mate the king early in the game. But here, it seems the only solution is to wear down your opponent's army. Defenses are pretty strong, and without a diagonal attack, the only real option is to simply wear your enemy down till there are no longer enough defenders. Definitely gives the game a different flavor.