h#8.5
8/7k/N7/8/8/8/4r3/Kq6 w - - 0 1
- Kxb1 Kg6 Nb4 Kf5 Nc2 Ke4 Kb2 Kd3 Kc1 Kc3 Kd1 Kb2 Nd4 Ka1 Kc1 Ra2 Nb3#
pure model ideal switchback self-block nocheck
Note: the side to move is in check in the diagram; the solution begins with a capture.
5 pieces.
8/7k/N7/8/8/8/4r3/Kq6 w - - 0 1
pure model ideal switchback self-block nocheck
Note: the side to move is in check in the diagram; the solution begins with a capture.
8/8/8/8/8/7k/5r1N/qK6 w - - 0 1
pure model ideal switchback self-block kniest
Note: the side to move is in check in the diagram; the solution begins with a capture.
6k1/8/8/1r6/8/8/2q5/2K2N2 w - - 0 1
pure model ideal switchback self-block nocheck
Note: the side to move is in check in the diagram; the solution begins with a capture.
Deepest dual with different first and last moves: h#6.5. The deepest dual overall is h#8.5, where the two solutions share a first or a last move.
8/8/8/5k2/q7/r7/7N/K7 w - - 0 1
Two solutions, with different first and last moves (2 starts, 2 ends).
pure model ideal self-block nocapture
Note: the side to move is in check in the diagram.