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This Falcon is a very nasy piece to program. The multi-path character of its moves subverts all properties of pinned pieces on which my engine Joker relies for efficient legal-move generation. There is no longer a well-defined pin line: pieces pinned by a Falcon can often move in multiple directions without exposing the King. Also it is no longer sure that a pinned slider cannot move along its pin line to block a check by another piece (if this other piece is a Falcon). A check by a Falcon can have the character of a contact check (for interposing is not an option if the King is checked through multiple paths) despite being inflicted from a distance.

I guess I will simply generate moves as if the enemy Falcons have no moves, (so generating pseudo-legal moves with pieces pinned by a Falcon, and with other pieces when in check by a Falcon), and then test for their legality afterwards (by testinng if an enemy Falcon happened to be aligned with our King, and then testing all the generated moves for leading to a position where this Falcon is sufficiently blocked). Cumbersome, but I don't see an efficient alternative.