Longest mate in King, Queen and Rook versus King endgame

Mate in 6

Also available in PGN notation.

White to move
Mate in 6 with Kg7, Kg8, Kh7, Qa7, Qb7, Qb8+, Qc6, Qc8, Qd8, Qe8+, Qf3, Qf8, Qg2, Qg8, Qh1, Ra1, Ra2, Ra3, Ra4, Ra5+, Ra7, Rb6, Rc6, Rg6 and Rh6. Worse are Rf6 with mate in 7, Rd6 and Re6+ with mate in 8, and Qd5+ and Qe4+ with mate in 17.
1. Ra5+
White mates in 5 after Kd4. Worse are Kd6 and Kf4 when White mates in 4, and Ke6 and Kf6 when White mates in 3.
1... Kd4
Mate in 5 with Kg7, Qc6, Qc8, Qd5+, Qe8, Qf3, Rb5 and Rf5. Worse are Kg8, Kh7, Qa6, Qa7+, Qb7, Qb8, Qd8+, Qf8, Qg2, Qg8, Qh1, Ra1, Ra3, Ra4+, Ra7, Rd5+, Rg5 and Rh5 with mate in 6, Ra2 and Ra6 with mate in 7, Re5 with mate in 9, Rc5 with mate in 10, and Qe4+ with mate in 16.
2. Qe8
White mates in 4 after Kc3, Kc4 and Kd3.
2... Kd3
Mate in 4 with Rd5+. Worse are Qa4, Qb5+, Qd7+, Qe5, Qe6, Ra3+, Ra4, Ra7 and Rc5 with mate in 5, Kg7, Kg8, Kh7, Qa8, Qb8, Qc6, Qc8, Qd8+, Qe1, Qe7, Qf7, Qf8, Qg6+, Qg8, Qh5, Ra1, Ra2, Ra6, Ra8, Rb5, Re5, Rf5, Rg5 and Rh5 with mate in 6, Qe2+ with mate in 15, and Qe3+ and Qe4+ with mate in 16.
3. Rd5+
White mates in 3 after Kc2, Kc3 and Kc4.
3... Kc4
Mate in 3 with Qc6+. Worse are Qa8, Qb5+, Qd7, Qd8, Qe4+, Qe6 and Rd7 with mate in 4, Qe5, Qf7, Qg8, Qh5, Rd1, Rd2, Rd6 and Rd8 with mate in 5, Ra5, Rb5, Re5, Rf5, Rg5 and Rh5 with mate in 6, Qa4+, Qb8, Qe1, Qe7 and Qf8 with mate in 8, Kg7, Kg8, Kh7, Qc8+ and Qe3 with mate in 9, and Qe2+, Qg6, Rc5+, Rd3 and Rd4+ with mate in 10.
4. Qc6+
White mates in 2 after Kb3 and Kb4.
4... Kb4
Mate in 2 with Rb5+. Worse are Kg7, Kg8, Kh7, Qc7, Qc8, Rc5, Rd8, Re5, Rf5, Rg5 and Rh5 with mate in 3, Qa6, Qa8, Qb5+, Qb6+, Qb7+, Qc1, Qc2, Qc5+, Qd6+, Qd7, Qe6, Qe8, Qf6, Qg6, Qh6, Rd1, Rd2, Rd3, Rd4+, Rd6 and Rd7 with mate in 4, Ra5 with mate in 8, Qa4+ with mate in 14, Qc3+ with mate in 15, and Qc4+ with mate in 16.
5. Rb5+
White mates in 1 after Ka3 and Ka4.
5... Ka4
Mate in 1 with Qa6#. Worse are Kg7, Kg8, Kh7, Qb6, Qb7, Qc4+, Qd5, Qd7, Qe8, Rb1+, Rb6+, Rb7+ and Rb8+ with mate in 2, Rb2+, Rc5+, Rd5+, Re5+, Rf5+, Rg5+ and Rh5+ with mate in 3, Qc2+, Qc3 and Ra5+ with mate in 8, Qc1, Qc7, Qc8, Qe4+, Qf3, Qf6, Rb3+ and Rb4+ with mate in 9, Qa8+, Qd6, Qe6, Qg2, Qg6, Qh1 and Qh6 with mate in 10, and Qc5 which throws away the win.
6. Qa6#
Checkmate.
1-0


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