[Event "?"] [Site "?"] [Date "????.??.??"] [Round "?"] [White "White to play and win"] [Black "?"] [Result "*"] [Annotator "peter"] [SetUp "1"] [FEN "8/1Pr5/1R5P/8/8/8/p7/k5K1 w - - 0 1"] [PlyCount "21"] [EventType "team-tourn"] [EventRounds "15"] [SourceVersionDate "2020.04.01"] {[#]} {Black's defence is based on stalemate, so White must avoid that whilst being able to stop the a-pawn from queening.} 1. b8=B $1 (1. h7 $11 {This is perhaps the best try apart from the solution, aiming to reach the a-file with the king. However, even this does not avoid stalemate.} Rxh7 2. b8=Q Rh1+ 3. Kf2 Rf1+ 4. Ke3 Re1+ 5. Kd4 Rd1+ 6. Kc5 Rc1+ 7. Kb5 Rc5+ 8. Ka6 (8. Ka4 Ra5+ 9. Kb3 Ra3+ 10. Kc2 Rc3+) 8... Ra5+) (1. b8=Q $11 Rc1+ 2. Kf2 Rc2+ 3. Ke3 Rc3+ 4. Kd4 Rc4+ 5. Kd5 Rc5+ 6. Kd6 Rc6+ {etc}) (1. b8=R $11 Rc1+ {etc}) 1... Rc1+ 2. Kf2 Rc2+ 3. Ke3 Rc3+ 4. Kd4 Rc4+ 5. Kd5 {And now there are several lines but White can always wriggle out of the stalemate, e.g.} Rc5+ (5... Rd4+ 6. Ke6 Re4+ 7. Kd7 Re7+ 8. Kc6 Rc7+ 9. Kd5 Rc5+ 10. Ke6) 6. Kd6 Rd5+ (6... Rc6+ 7. Rxc6 $18) 7. Ke7 Rd7+ (7... Re5+ 8. Bxe5#) 8. Ke6 Re7+ 9. Kd5 Rd7+ (9... Re5+ 10. Bxe5#) 10. Bd6 Rd8 11. h7 $18 *