h#7.5
8/8/8/8/6k1/1b6/1N6/Kr6 w - - 0 1
- Kxb1 Kf3 Nc4 Ke2 Kb2 Kd1 Kc3 Kc1 Ne3 Kb1 Kd2 Ka1 Kc1 Ba2 Nc2#
pure model ideal self-block nocheck
Note: the side to move is in check in the diagram; the solution begins with a capture.
5 pieces.
8/8/8/8/6k1/1b6/1N6/Kr6 w - - 0 1
pure model ideal self-block nocheck
Note: the side to move is in check in the diagram; the solution begins with a capture.
8/3k4/8/8/8/4b3/2N5/3Kr3 w - - 0 1
pure model ideal self-block umnov
Note: the side to move is in check in the diagram; the solution begins with a capture.
8/6k1/8/8/8/3b4/3N4/3K1r2 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#7.5, where the two solutions share a first or a last move.
8/8/4k3/8/8/8/N1rb4/1K6 w - - 0 1
Two solutions, with different first and last moves (2 starts, 2 ends).
4k3/8/8/2r5/8/4b3/8/1KN5 w - - 0 1
Two solutions, with different first and last moves (2 starts, 2 ends).