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The mating corners (the bishop's colour)
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The idea
Mate is only possible in a corner of the bishop's colour: drive the king to the edge, then walk it along the edge to the right corner with the knight's W manoeuvre.
Two corners are safe for the king; the other two are where it gets mated.
- Use king, bishop and knight together to drive the king to an edge.
- If it runs to the wrong corner (not the bishop's colour), herd it along the edge towards the right one.
- The knight moves in a W shape (for example Nd7, Nc5, Nb3, Na5 near the corner), taking the squares the bishop cannot.
- Mate in the right corner, where the bishop delivers check along the long diagonal.
- You have 50 moves: the technique takes up to 33, so be efficient.
Press Next (or →) to watch the technique, move by move. Your side starts.
Every verdict comes from the Lichess tablebase (exact for seven pieces or fewer).