[zzssyrxk] 10x10 chess

Chess can straightforwardly be extended to a 10x10 board (or larger) without adding radically new piece types like archbishop or chancellor.

Instead, in addition to the 8 traditional pieces on the first and eighth ranks, the two additional spaces could be some subset of:
* Leave it empty
* An additional queen
* A "Man", a non-royal piece that moves like a king but can be captured without losing the game
* Two more bishops
* More knights or rooks
* More pawns (on the first rank, beginning doubled!)