Bishop & Knight Checkmate
The technique that separates real endgame players
King, bishop and knight versus king is a forced win, but only into a corner of the bishop's color, and only within at most 33 accurate moves. Grandmasters have failed it over the board. That is exactly why it is worth owning.
Play this ending (free)Why this mate is different
Bishop and knight control different colors, so they can never build the tidy wall two bishops make. Worse, mate can only be delivered in a corner the bishop controls: with a light-squared bishop, a8 or h1. The defender knows this and sprints for a wrong-colored corner, where no mate exists.
So the ending has three phases: drive the king to the edge (any edge), escort it out of the wrong corner, and mate it in the right one. Phase two is the famous part.
The W maneuver
To evict the king from the wrong corner and march it along the edge to the right one, the knight travels a W-shaped path, zigzagging between two ranks (driving a king along the 8th rank, the knight bounces between the 7th and 5th) while king and bishop take turns sealing the escape squares behind it. Each zigzag of the W hands the defending king one forced step in the right direction.
Don't memorize squares. Learn the cage: at every moment, king, bishop and knight form a shrinking pocket whose only exit points toward the mating corner. The knight is the slow piece, so it moves early; the bishop is the fast one, so it does the last-second sealing. Played this way, the whole eviction takes about ten moves.
Train it or lose it
This is the mate where practice against perfect defense is non-negotiable: a tablebase defender takes the longest legal road to the wrong corner, punishes every inaccuracy with a reset toward the center, and makes the 50-move rule a real deadline. If you can convert bishop and knight against a tablebase, no human will ever escape you.
It is also, honestly, a rite of passage: the ending occurs rarely, but the piece coordination it teaches (three pieces working as one cage) upgrades every endgame you play.
Questions
In which corner can bishop and knight checkmate?
Only in a corner of the bishop's color: with a light-squared bishop, a8 or h1; with a dark-squared bishop, a1 or h8. In the other two corners no forced mate exists, which is why the defender runs there.
How many moves does the bishop and knight mate need?
At most 33 moves from the worst winning position with perfect play: inside the 50-move rule, but with far less slack than any other basic mate. Sloppy technique regularly burns the budget.
Has anyone actually failed this mate in a real game?
Yes, including grandmasters and even world-class players: draws by the 50-move rule in bishop-and-knight endings happen at every level. It is the standard example of a technique you must drill before you need it.
Why can't a king and a single bishop checkmate?
One bishop (or one knight) alone cannot cover all the escape squares around the enemy king: it is insufficient mating material and the game is a draw. Adding the knight to the bishop is exactly what makes a forced mate possible.
What is the W maneuver?
The knight's zigzag path used to escort the defending king from the safe (wrong-colored) corner along the edge to the mating corner. Its route traces a W shape while the king and bishop seal the escape squares.
Don't just read it, play it
Every position below is playable right now, free, no signup, against a tablebase-perfect opponent that never gives up and explains every mistake.
Follow the full curriculum (free)or sharpen these endings in the Gym