@Rocky64
Not totally relevant, but this is the board layout shown by chess.com if you play 1...Qb1 in @adam_7000's puzzle here https://www.chess.com/forum/view/more-puzzles/whats-the-answer-of-this-position-54920200?page=2. (Presumably stalemate.)
Impossible-to-reach position with the least amount of pieces?
Sort:
@DjVortex
Wouldn't Buchanan's position (post #12) count? I didn't think it was immediately obvious.