h#6
8/8/8/1r4k1/6R1/8/3r4/K7 b - - 0 1
- Kf5 Rg5+ Ke4 Rxb5 Kd3 Ra5 Kc2 Ka2 Kd1+ Kb3 Kc1 Ra1#
pure model ideal single-piece single-piece:black umnov
Note: the side to move is in check in the diagram.
5 pieces.
8/8/8/1r4k1/6R1/8/3r4/K7 b - - 0 1
pure model ideal single-piece single-piece:black umnov
Note: the side to move is in check in the diagram.
8/8/5kR1/8/8/7r/5r2/K7 b - - 0 1
switchback self-block nocapture
Note: the side to move is in check in the diagram.
8/8/6Rk/8/8/1r2r3/8/K7 b - - 0 1
pure model ideal mirror single-piece single-piece:black
Note: the side to move is in check in the diagram.
Deepest dual with different first and last moves: h#5.5. The deepest dual overall is h#6, where the two solutions share a first or a last move.
5kr1/8/8/7R/8/8/3r4/1K6 w - - 0 1
Two solutions, with different first and last moves (2 starts, 2 ends).