[Retros] En Passant Chess

[Noam Elkies]

> I would share with you all my idea about a variant chess I invented.

> [...] I call it:" En Passant Chess ".They are like normal chess,

> except that all pieces (King too) and pawns are allowed to capture

> (next move) an enemy piece, just moved, which traversed a square

> under its control.



> Examples:

> 1 e4,e5 ;  2 Bc4, Bc5 ; 3 Qf3, Nc6 4 Qxf7 isn't mate because:

> 4...,e5xQf4  or  4...,g7xQf6    or   4....,NxQf6

> or  4....,QxQf6 and if 4 Bxf7? then  4...d7xBe6.



> [...]


Interesting.  This could be nice for non-retro fairy problems too.

If the piece being captured just made a capture itself, is the captured
piece restored?  If so, can 4 Bxf7+ be answered also by 4...Kxf7,
and then if 5 Qxf7 then (say) NxQf6 restoring the Kf7?

--Noam D. Elkies