[Event "The bakery (blog diagram workshop): Breaker - K+B (K boxes, B seals)"] [Site "https://lichess.org/study/l6bOrnM0"] [Date "2017.10.13"] [Result "*"] [Annotator "https://lichess.org/@/Illion"] [Variant "Atomic"] [ECO "?"] [Opening "?"] [StudyName "Atomic endgames: Pawnitisation"] [ChapterName "Breaker - K+B"] [ChapterURL "https://lichess.org/study/iS3Dp19A/Q9Pzmmem"] [FEN "3k4/2p1p3/8/1P3P2/3K4/3B4/8/8 w - - 0 1"] [SetUp "1"] [UTCDate "2017.10.13"] [UTCTime "19:41:19"] [Orientation "white"] { White to play and win. We notice that black's king is nearly trapped - the whole 7th rank except d7 and h7 is mined. So as white, we need to force black's king into zugzwang, but this can be accomplished only with both bishop and king. } 1. Be4 { Note the mining. White will attempt to bring the bishop in with black's king. } { [%csl Ra7,Rb7,Rc7,Rg7,Re7,Rf7,Re6,Rc6,Re5,Rc5][%cal Rb5b6,Rf5f6] } 1... Ke8 (1... Kd7 2. Bc6+ Kc8 (2... Kd6 3. Kd3 $22 { Black's king has been trapped between the 3x3 mined squares with no escape. } 3... Kc5 4. b6 Kd4 5. b7 $18) 3. Bd7+ Kb8 4. Bc8 { It turns out that here, the white bishop alone suffices. } 4... Ka8 5. Bb7+ Kb8 6. Ke3 Ka7 7. b6+ Kb8 8. bxc7#) 2. Bc6+ Kf8 3. Bd5 { Covering g8, preventing escape. Simplest. } (3. Be8 { Alternatively, covering h7 also prevents escape, but it's less straightforward to force the zugzwang. } 3... Kg8 4. Bg6 Kf8 { Now bringing white's king to g8 will result in zugzwang, with some intricate manoeuvring in the corner after arriving on g8. This is left as an exercise for the reader. }) 3... Ke8 4. Ke4 Kf8 5. Kf4 (5. Bf7? { Not this pattern, which blocks white's pawn. } 5... Kg7 6. f6+ Kh6 7. Bh5 exf6 $10) 5... Ke8 6. Kg5 Kf8 7. Kh6 Ke8 8. Kg7 Kf8 9. Kg8 { Amidst black's shuffling, white has brought the king to g8, and will box black's king back into the pawns for zugzwang. Both the king and the bishop are needed for this. } 9... Ke8 10. Kf8 (10. Bf7+ { Using the bishop is also viable. } 10... Kd7 (10... Kf8 11. Be8 $22 { This shows why the white king is needed. }) (10... Kd8 11. Be8 Kc8 12. Bd7+ Kb8 13. Bc8 Ka8 14. Bb7+ Ka7 15. b6+ { On the queenside, black doesn't have enough room to escape. } 15... Kb8 16. bxc7#) 11. Be8+ Kd6 12. Bc6 $22) 10... Kd7 (10... Kd8 11. Be6 Ke8 12. Bd7 Kd8 13. Kg8 $22) 11. Be6+ Kd8 (11... Kd6 12. Kg8 $22) 12. Bc8 Ke8 13. Bd7 Kd8 14. Kg8 $22 { There are many ways to force zugzwang at the end, not just the ones shown. The important lesson however is to be aware that both the king and the bishop must be used to force the zugzwang - hence the white king marching to g8. } *