Mini Hexchess

In April 21, 1997, Hans Bodlaender put a board with 37 squares on (t)his Internet Site on chess variants, asking which of his readers would compose a chess variant on the board by way of birthday present (he became 37 years old that day.) Dave McCooey, while thinking about the board, noticed that 37 is a hexagonal number, and that there is a perfect hexagonal board with 37 hexes. (About twenty years ago, Dave had invented a hexagonal chess variant, whose rules also can be found on the Chess Variant Pages.)

Dave wrote:

I couldn't miss the opportunity: the next perfect hex board will be when you're 61.

Rules

The rules of this game are the same as in McCooey's Hexagonal Chess, with the following differences:

1. There is no initial double step for the pawns, (and hence no en-passant capture.)
2. A pawn can promote to a rook, bishop, or knight, but not to a queen. All seven hexes on the opponents side of the board are promotion hexes.