Longest mate in King, Rook and Knight versus King endgame

Mate in 16

Also available in PGN notation.

White to move
Mate in 16 with Ra6, Rd6+, Re1, Re2, Re3, Re5+, Re7, Re8, Rg6 and Rh6. Worse are Rb6 and Rf6 with mate in 17, and Kg1, Kg2, Kh2, Na3, Na5, Nb2, Nb6+, Nd2, Nd6, Ne3+, Ne5, Rc6 and Re4 which throw away the win.
1. Re2
White mates in 15 after Kxc4. Worse are Kc5 and Kd4 when White mates in 12, and Kc6 when White mates in 11.
1... Kxc4
Mate in 15 with Kg2. Worse are Kg1, Kh2, Rd2, Re1, Re5, Re7, Re8 and Rh2 with mate in 16, and Ra2, Rb2, Rc2+, Re3, Re4+, Re6, Rf2 and Rg2 with mate in 17.
2. Kg2
White mates in 14 after Kc5, Kd3, Kd4 and Kd5. Worse are Kb4 and Kb5 when White mates in 13, and Kb3 and Kc3 when White mates in 11.
2... Kd3
Mate in 14 with Kf3. Worse are Kf2, Re1, Re5, Re6, Re7 and Re8 with mate in 15, Kf1, Ra2, Rb2 and Rf2 with mate in 16, and Kg1, Kg3, Kh1, Kh2, Kh3, Rc2, Rd2+, Re3+ and Re4 which throw away the win.
3. Kf3
White mates in 13 after Kd4. Worse are Kc4 when White mates in 12, and Kc3 when White mates in 11.
3... Kd4
Mate in 13 with Kf4, Rd2+ and Re4+. Worse are Kg3, Kg4, Ra2, Rb2, Rc2, Re1, Re3, Re6, Re7, Re8, Rf2, Rg2 and Rh2 with mate in 14, Kf2 and Kg2 with mate in 15, and Re5 which throws away the win.
4. Rd2+
White mates in 12 after Kc4. Worse are Kc3, Kc5 and Ke5 when White mates in 11.
4... Kc4
Mate in 12 with Ke3, Ke4, Kf4, Rd1, Rd7 and Rd8. Worse are Ke2 and Kf2 with mate in 13, Kg2, Kg3, Kg4, Ra2, Rb2, Rc2+, Rd6, Re2, Rf2, Rg2 and Rh2 with mate in 14, and Rd3, Rd4+ and Rd5 which throw away the win.
5. Ke3
White mates in 11 after Kc5. Worse are Kb4 when White mates in 10, Kb5 when White mates in 9, and Kb3 and Kc3 when White mates in 8.
5... Kc5
Mate in 11 with Ke4 and Rd4. Worse are Kf4, Rd1, Rd3, Rd7 and Rd8 with mate in 12, Kd3, Ke2, Kf2, Kf3, Ra2, Rb2, Rc2+, Re2, Rf2, Rg2 and Rh2 with mate in 13, and Rd5+ and Rd6 which throw away the win.
6. Ke4
White mates in 10 after Kb4, Kc4 and Kc6. Worse are Kb5 when White mates in 9, and Kb6 when White mates in 8.
6... Kc6
Mate in 10 with Rd5. Worse are Ke5 and Rd4 with mate in 11, Kd4, Ke3, Kf3, Kf4, Kf5, Ra2, Rb2, Rd1, Rd3, Rd8, Re2, Rf2, Rg2 and Rh2 with mate in 12, Kd3 and Rc2+ with mate in 13, and Rd6+ and Rd7 which throw away the win.
7. Rd5
White mates in 9 after Kb6, Kb7 and Kc7.
7... Kc7
Mate in 9 with Kd4 and Ke5. Worse are Kd3, Ke3, Kf4 and Kf5 with mate in 10, Kf3, Rd1, Rd2, Rd3, Rd4 and Re5 with mate in 11, Ra5, Rb5, Rc5+, Rf5, Rg5 and Rh5 with mate in 12, and Rd6, Rd7+ and Rd8 which throw away the win.
8. Ke5
White mates in 8 after Kc6. Worse are Kb6, Kb7, Kb8 and Kc8 when White mates in 6.
8... Kc6
Mate in 8 with Ke6. Worse are Kd4 with mate in 9, Ke4 and Ra5 with mate in 10, Rd1, Rd2, Rd3, Rd6+ and Rd8 with mate in 11, Rd4 with mate in 12, and Kf4, Kf5, Kf6, Rb5, Rc5+ and Rd7 which throw away the win.
9. Ke6
White mates in 7 after Kc7. Worse are Kb7 when White mates in 6, and Kb6 when White mates in 5.
9... Kc7
Mate in 7 with Rc5+ and Rd6. Worse are Ke7, Re5, Rf5, Rg5 and Rh5 with mate in 8, Ke5, Kf6, Kf7, Ra5, Rb5, Rd1, Rd2, Rd3, Rd4 and Rd7+ with mate in 9, Kf5 with mate in 10, and Rd8 which throws away the win.
10. Rd6
White mates in 6 after Kc8. Worse are Kb8 when White mates in 5, and Kb7 when White mates in 4.
10... Kc8
Mate in 6 with Rc6+ and Rd7. Worse are Ke7 with mate in 7, Kd5, Ke5, Kf5, Kf6, Kf7, Ra6, Rb6, Rd1, Rd2, Rd3, Rd4 and Rd5 with mate in 8, and Rd8+ which throws away the win.
11. Rc6+
White mates in 5 after Kb7 and Kb8. Worse is Kd8 when White mates in 2.
11... Kb8
Mate in 5 with Kd7. Worse are Kd6 and Ke7 with mate in 6, Kd5, Ke5, Rc5 and Rd6 with mate in 7, Kf7, Ra6, Rb6+, Rc1, Rc2, Rc3 and Rc4 with mate in 8, Kf5 and Kf6 with mate in 9, and Rc7 and Rc8+ which throw away the win.
12. Kd7
White mates in 4 after Kb7. Worse are Ka8 when White mates in 3, and Ka7 when White mates in 2.
12... Kb7
Mate in 4 with Rd6, Re6, Rf6, Rg6 and Rh6. Worse are Kd6 with mate in 5, Rc5 with mate in 6, Rc4 with mate in 9, Rc1, Rc2, Rc3, Rc7+ and Rc8 with mate in 11, and Kd8, Ke6, Ke7, Ke8, Ra6 and Rb6+ which throw away the win.
13. Rf6
White mates in 3 after Ka8 and Kb8. Worse is Ka7 when White mates in 2.
13... Kb8
Mate in 3 with Kc6. Worse are Rb6+ with mate in 4, Kd6, Kd8, Ra6, Rc6, Rd6, Re6, Rf1, Rf2, Rf3, Rf4, Rf5, Rf7, Rf8+, Rg6 and Rh6 with mate in 5, and Ke6, Ke7 and Ke8 with mate in 7.
14. Kc6
White mates in 2 after Ka7 and Ka8. Worse is Kc8 when White mates in 1.
14... Ka8
Mate in 2 with Kb6. Worse are Kc7, Rf1, Rf2, Rf3, Rf4, Rf5 and Rf8+ with mate in 3, Rd6, Re6, Rf7, Rg6 and Rh6 with mate in 4, Kd6 and Kd7 with mate in 5, Kb5 and Kc5 with mate in 6, and Kd5 with mate in 8.
15. Kb6
White mates in 1 after Kb8.
15... Kb8
Mate in 1 with Rf8#. Worse are Rc6 with mate in 2, Kc6, Rd6, Re6, Rf1, Rf2, Rf3, Rf4, Rf5, Rg6 and Rh6 with mate in 3, Kc5 and Rf7 with mate in 7, Kb5 with mate in 11, and Ka5 and Ka6 with mate in 12.
16. Rf8#
Checkmate.
1-0


An endgame analysis by Joe Leslie-Hurd on 16 February 2005.