[mpyfvglu] pawn promotion to god

2 closely related chess variants:

1. pawn promotion (pawn reaching 8th rank) causes immediate victory.
2. if a pawn promotes, it must immediately be captured next turn by the opposing player.  if not, victory for the promoter.  not even checkmate is a sufficient response.  (is king capture a sufficient response?  probably best to leave in place the standard rule that no move, not even pawn promotion, may leave your king in check.)  this can be thought of as the pawn promoting to a piece with infinite power, so checks the opposing king from anywhere.

inspired by endgame tablebases with fairy chess pieces.  there become too many possibilities of what a pawn can promote to.

further possibility: eliminate checkmate; king is not a special piece.  (also eliminate castling.)  pawn race to promotion is the only goal.  this is similar to Breakthrough by Dan Troyka.  also similar to tower defense or lemmings (escort quest).  pawnless engames are draws: do we want a way to reintroduce pawns, e.g., Shogi drops?

in chess variants in which black is guaranteed the same number of moves, black could respond to pawn promotion also with pawn promotion.  then what?  draw, or promoted pawns annihilate?