%TITLE Longest mate in King and Bishop versus King and Bishop endgame: an endgame analysis by Joe Leslie-Hurd
%HEADING Longest mate in King and Bishop versus King and Bishop endgame
%SUBHEADING Mate in 1
%FOOTER An <a href="http://www.gilith/chess/endgames">endgame analysis</a> by <a href="http://www.gilith.com/">Joe Leslie-Hurd</a> on 16 February 2005.

[Event "Endgame analysis: longest mate in King and Queen versus King and Bishop"]
[Site "Oxford ENG"]
[Date "2005.02.16"]
[Round "-"]
[White "Perfect"]
[Black "Perfect"]
[Result "1-0"]
[Time "05:27:19"]
[Annotator "Joe Leslie-Hurd"]
[WhiteType "program"]
[BlackType "program"]
[SetUp "1"]
[FEN "7Q/8/8/4b3/3k4/8/8/K7 w - - 0 1"]

{Mate in 17 with Qa8, Qc8, Qd8+, Qe8, Qf8, Qg8, Qh1, Qh3, Qh4+, Qh5, Qh6 and Qh7. Worse are Ka2, Kb1, Kb2, Qb8, Qf6, Qg7, Qh2 and Qxe5+ which throw away the win.}
1. Qe8 {White mates in 16 after Bf6, Kd5+ and Ke4+. Worse are Bd6, Bf4 and Bg3 when White mates in 15, Bh2 when White mates in 14, Bc7 and Bg7 when White mates in 11, Bb8 when White mates in 10, Bh8, Kc5+ and Ke3+ when White mates in 9, and Kc3, Kc4+ and Kd3+ when White mates in 6.}
1... Bf6 {Mate in 16 with Ka2, Kb1, Kb2, Qa4+, Qa8, Qb5, Qc6, Qd7+, Qe1, Qe2, Qe6, Qf7, Qg6 and Qh5. Worse are Qb8, Qc8, Qf8 and Qg8 with mate in 17, and Qd8+, Qe3+, Qe4+, Qe5+, Qe7 and Qh8 which throw away the win.}
2. Kb1 {White mates in 15 after Be5. Worse are Bg5 and Kd5 when White mates in 14, Bg7 and Bh4 when White mates in 10, Bd8, Bh8, Kc3, Kc4, Kc5 and Kd3 when White mates in 9, and Be7 when White mates in 8.}
2... Be5 {Mate in 15 with Kb2, Kc1, Kc2, Qb5, Qe6 and Qe7. Worse are Ka2, Qa4+, Qa8, Qc6, Qc8, Qd7+, Qd8+, Qf7, Qf8, Qg6, Qg8 and Qh5 with mate in 16, Ka1 with mate in 17, and Qb8, Qh8 and Qxe5+ which throw away the win.}
3. Qe6 {White mates in 14 after Bf4 and Ke4. Worse are Bh2 when White mates in 12, Bg3 and Bh8 when White mates in 11, Bb8, Bc7 and Bg7 when White mates in 10, Kc5 when White mates in 9, Bd6, Bf6 and Ke3 when White mates in 8, and Kc3 and Kd3 when White mates in 6.}
3... Bf4 {Mate in 14 with Kc2 and Qg4. Worse are Ka2, Kb2, Qd7+, Qe2, Qf5, Qg6 and Qh3 with mate in 15, Ka1, Qa2, Qa6, Qb3, Qb6+, Qc6, Qc8, Qe1, Qe7, Qe8, Qf6+, Qf7 and Qg8 with mate in 16, and Qc4+, Qd5+, Qd6+, Qe3+, Qe4+, Qe5+ and Qh6 which throw away the win.}
4. Kc2 {White mates in 13 after Be5. Worse are Be3 and Bh2 when White mates in 11, Bg3 when White mates in 10, Bb8, Bc7, Bg5 and Kc5 when White mates in 9, Bh6 when White mates in 8, Bc1 and Bd6 when White mates in 7, and Bd2 when White mates in 5.}
4... Be5 {Mate in 13 with Kd1 and Kd2. Worse are Kb3, Qb6+, Qd7+, Qf5, Qg4+, Qg6 and Qh3 with mate in 14, Kb1, Kb2, Kc1, Qa2, Qa6, Qb3, Qc6, Qc8, Qe7, Qe8, Qf7, Qg8 and Qh6 with mate in 15, and Qc4+, Qd5+, Qd6+, Qf6 and Qxe5+ which throw away the win.}
5. Kd2 {White mates in 12 after Bf4+ and Ke4. Worse are Bh2 when White mates in 11, Bg3 and Bh8 when White mates in 10, Bb8, Bc7 and Bg7 when White mates in 9, Kc5 when White mates in 8, Bf6 when White mates in 7, and Bd6 when White mates in 6.}
5... Ke4 {Mate in 12 with Ke2. Worse are Qc4+ and Qg6+ with mate in 13, Kc1, Kc2, Kd1, Ke1, Qa2, Qa6, Qb6, Qc6+, Qd7, Qe7, Qe8, Qf7 and Qg4+ with mate in 14, Qb3, Qc8, Qg8 and Qh3 with mate in 15, and Qd5+, Qd6, Qf5+, Qf6, Qh6 and Qxe5+ which throw away the win.}
6. Ke2 {White mates in 11 after Kd4 and Kf4.}
6... Kd4 {Mate in 11 with Kf3. Worse are Qd7+ with mate in 12, Kd1, Kd2, Kf1, Kf2, Qa6, Qb6+, Qc6, Qe7 and Qg6 with mate in 13, Ke1, Qa2, Qb3, Qc8, Qe8, Qf5, Qf7, Qg4+, Qg8, Qh3 and Qh6 with mate in 14, and Qc4+, Qd5+, Qd6+, Qf6 and Qxe5+ which throw away the win.}
7. Kf3 {White mates in 10 after Bh2 and Bh8. Worse are Bb8, Bc7 and Bg7 when White mates in 9, Bf6, Bg3 and Kc5 when White mates in 8, and Bd6, Bf4, Kc3 and Kd3 when White mates in 7.}
7... Bh2 {Mate in 10 with Qe3+. Worse are Qb6+, Qc6, Qd7+ and Qe4+ with mate in 11, Kg4, Qa6, Qe7, Qf6+, Qg4+ and Qh6 with mate in 12, Ke2, Kf2, Kg2, Qe1, Qe2, Qe8, Qf5 and Qg6 with mate in 13, Qa2, Qb3, Qc8, Qf7, Qg8 and Qh3 with mate in 14, and Qc4+, Qd5+, Qd6+ and Qe5+ which throw away the win.}
8. Qe3+ {White mates in 9 after Kc4 and Kd5.}
8... Kd5 {Mate in 9 with Qd2+. Worse are Qb3+ with mate in 10, Qd3+ with mate in 11, Qe4+ and Qg5+ with mate in 12, Ke2, Kg4, Qe1, Qe2, Qe7 and Qe8 with mate in 13, Kf2, Kg2, Qa3, Qa7, Qb6, Qc1, Qc3, Qf2 and Qh6 with mate in 14, and Qc5+, Qd4+, Qe5+, Qe6+, Qf4 and Qg1 which throw away the win.}
9. Qd2+ {White mates in 8 after Kc4, Kc5, Kc6, Ke5 and Ke6.}
9... Kc5 {Mate in 8 with Qxh2. Worse are Ke4, Qc2+ and Qf2+ with mate in 9, Qc1+ and Qc3+ with mate in 10, Ke3, Qa2, Qa5+, Qd1, Qd3, Qd7, Qd8, Qe3+ and Qg5+ with mate in 11, Ke2, Kf2, Kg2, Kg4, Qb2, Qe1, Qe2, Qg2 and Qh6 with mate in 12, and Qb4+, Qd4+, Qd5+, Qd6+ and Qf4 which throw away the win.}
10. Qxh2 {White mates in 7 after Kb4, Kb6, Kc4, Kc6, Kd4 and Kd5. Worse is Kb5 when White mates in 6.}
10... Kc6 {Mate in 7 with Ke4. Worse are Ke2, Ke3, Kf4, Qa2, Qb2, Qb8, Qc2+, Qd2, Qe2, Qe5, Qf2, Qf4, Qg1, Qg2, Qg3, Qh1, Qh3, Qh4, Qh5, Qh6+, Qh7 and Qh8 with mate in 8, Kf2, Kg2, Kg3 and Kg4 with mate in 9, and Qc7+ and Qd6+ which throw away the win.}
11. Ke4 {White mates in 6 after Kc5. Worse are Kb6 and Kd7 when White mates in 5, and Kb5 and Kb7 when White mates in 4.}
11... Kc5 {Mate in 6 with Qc7+ and Qh6. Worse are Ke5, Qa2, Qb2, Qb8, Qc2+, Qd2, Qe2, Qe5+, Qf2+, Qf4, Qg1+, Qg2, Qg3, Qh1, Qh3, Qh4, Qh5+ and Qh8 with mate in 7, Kd3, Ke3, Kf3, Kf4, Kf5 and Qh7 with mate in 8, and Qd6+ which throws away the win.}
12. Qc7+ {White mates in 5 after Kb4. Worse is Kb5 when White mates in 4.}
12... Kb4 {Mate in 5 with Kd3, Kd4, Ke3 and Qc6. Worse are Kd5, Ke5, Qa7, Qb6+, Qc1, Qc2, Qc8, Qd6+, Qd7, Qd8 and Qe5 with mate in 6, Kf3, Kf4, Kf5, Qb7+, Qb8+, Qe7+, Qf4, Qf7, Qg3, Qg7, Qh2 and Qh7 with mate in 7, and Qa5+, Qc3+, Qc4+ and Qc5+ which throw away the win.}
13. Kd3 {White mates in 4 after Kb5. Worse are Ka3, Ka4 and Kb3 when White mates in 3.}
13... Kb5 {Mate in 4 with Kc3, Kd4 and Qd6. Worse are Kc2 and Qd7+ with mate in 5, Kd2, Ke2, Ke3, Ke4, Qb7+, Qc2, Qc3, Qc4+, Qc8, Qd8 and Qe7 with mate in 6, Qa7, Qb8+, Qc1, Qe5+, Qf4, Qf7, Qg3, Qg7, Qh2 and Qh7 with mate in 7, and Qa5+, Qb6+, Qc5+ and Qc6+ which throw away the win.}
14. Kc3 {White mates in 3 after Ka6. Worse is Ka4 when White mates in 2.}
14... Ka6 {Mate in 3 with Qb8. Worse are Kb3, Kd4 and Qd7 with mate in 4, Kb2, Kc2, Kd2 and Kd3 with mate in 5, Qc5, Qc6+, Qc8+, Qd6+, Qd8, Qe7, Qf7, Qg7 and Qh7 with mate in 6, Qc4+, Qe5, Qf4, Qg3 and Qh2 with mate in 7, and Kb4, Kc4, Qa5+, Qa7+, Qb6+ and Qb7+ which throw away the win.}
15. Qb8 {White mates in 2 after Ka5.}
15... Ka5 {Mate in 2 with Qb7. Worse are Kb3, Kc4, Kd3 and Kd4 with mate in 3, Kb2, Kc2, Kd2, Qb1, Qb2, Qb3, Qb4+, Qc7+, Qd6 and Qd8+ with mate in 4, Qa7+ with mate in 5, Qa8+, Qc8, Qe5+, Qe8, Qf8, Qg8 and Qh8 with mate in 6, Qf4, Qg3 and Qh2 with mate in 7, and Qb5+ and Qb6+ which throw away the win.}
16. Qb7 {White mates in 1 after Ka4.}
16... Ka4 {Mate in 1 with Qa6# and Qb4#. Worse are Kc4, Qb6 and Qd5 with mate in 2, Kb2, Kc2, Kd2, Kd3, Kd4, Qb1, Qb2, Qb3+, Qb8, Qc6+ and Qd7+ with mate in 3, Qc7 and Qe7 with mate in 4, Qa7+, Qc8, Qf7, Qg7 and Qh7 with mate in 5, Qa8+, Qe4+, Qf3, Qg2 and Qh1 with mate in 6, and Qb5+ which throws away the win.}
17. Qa6# {Checkmate.} 1-0
