How to checkmate with bishop and knight
Learn the bishop and knight mate as a pattern you can repeat: push the king to the dark corner, then the knight walks a W along the edge, your king walks beside it, and the bishop mates in the right corner.
Push the king to the dark corner
Bishop and knight mate only in a corner of the bishop's colour, and the king will run for a dark one. Push it there: your king leads, the bishop takes the light squares and the knight the dark ones.
Your bishop is light, so mate happens in a8 or h1. The king will run for a dark corner, a1 or h8. Your king leads the way: play Kd2. Kd2 Kd4
1… Kd4 The king comes forward to d4, face to face with your king.
Play Bd3: the bishop takes the light squares c4 and e4 in front of the king, and your king guards it. Bd3 Kc5
2… Kc5 The king steps back to c5.
Play Ke3: your king walks up and takes d4. Ke3 Kd5
3… Kd5 It comes back to d5.
Play Kf4: your king climbs a rank and takes e4 and e5. Kf4 Ke6
4… Ke6 The king goes to e6.
Play Bc4+: a check from far away. The bishop takes d5 and f7, and the king has to step aside. Bc4+ Kf6
5… Kf6 It steps aside to f6, towards h8, a dark corner where it is safe.
Now the knight joins in to take the dark squares: play Nd2, on its way to f3. Nd2 Kg6
6… Kg6 It keeps heading for the dark corner: g6.
Play Nf3: the knight takes the dark squares g5 and h4, so the king can't come back down the board. Nf3 Kh5
7… Kh5 The king goes to the edge, h5.
Play Kf5: your king takes g4, g5 and g6, and h6 is the only square left. Kf5 Kh6
8… Kh6 h6 was its only move.
Play Kf6: your king follows and takes g6 and g7. From f6 it watches the h8 corner. Kf6 Kh7
9… Kh7 The king goes up to h7, next to its dark corner.
The king is at the edge next to h8, the dark corner, and your king stands on f6. From here the pattern starts.
Into the corner, shut the door
From the dark corner the knight walks a W along the back rank: f7, e5, d7, c5, b7. First it steps onto the W, and the bishop shuts the way back to h8.
The knight only ever stands on the green squares of the W. Play Ne5: it is on the W, one jump from f7. Ne5 Kh8
10… Kh8 The king hides in its corner, h8.
Play Bd3: the bishop takes h7, and the king has only g8. Bd3 Kg8
11… Kg8 Its only move: g8.
Play Nf7, the first point of the W: the knight takes h8, so the king can't go back to its corner. No check with the bishop: Bh7+ would just lose it. Nf7 Kf8
12… Kf8 Its only move: f8.
Now the bishop can go: play Bh7. It shuts g8, the door back to the corner, and the king has to walk along the back rank. Bh7 Ke8
13… Ke8 Its only move: e8.
The king is out of its corner and the door is shut. Now the knight walks the W, and your king walks beside it.
The knight and the king walk together
Each jump of the knight is one file closer to a8. Your king walks the 6th rank beside it, one step at a time, and never goes back.
Play Ne5, the second point of the W: the knight takes d7. Ne5 Kd8
14… Kd8 The king walks on along the back rank, to d8.
Now your king: play Ke6, one step along the 6th rank. From e6 it will guard the knight on d7. Ke6 Kc7
15… Kc7 The king tries to run out towards b6 and c5, starting with c7.
Play Nd7, the third point of the W and the key move: the knight takes b6 and c5, the two squares the king was running for, and your king guards it. Nd7 Kb7
16… Kb7 The king goes to b7.
Three points of the W: f7, e5, d7. The king is on b7 and still looks for a way out through a6 and b5. That is the bishop's job.
The bishop shuts the box
The bishop leaves h7 and shuts the king in from far away, without a check. When nothing needs doing, it waits on its diagonal.
Play Bd3: the bishop takes a6 and b5, and the king is locked in the shaded box. Bd3 Kc6
17… Kc6 The king comes out to c6.
Nothing new to shut here, so make a waiting move that keeps the box: play Be2, along the same diagonal. Bb5+ would only lose the bishop. Be2 Kc7
18… Kc7 It steps back to c7.
Play Bf3: the bishop takes the long diagonal, closing b7 and c6, and the box shrinks to four squares. Bf3 Kd8
19… Kd8 The king goes to d8.
Your king's turn: play Kd6, the next step along the 6th rank. It takes c7. Kd6 Ke8
20… Ke8 The king heads for f7: with your king gone from e6, nothing covers it.
Your king stands on d6 and the knight on d7. The king wants out through f7, and the bishop is about to shut it.
Finish the W
The bishop shuts the back door, then the knight makes the last two jumps of the W, c5 and b7, and your king walks with it to b6.
Play Bd5: the bishop takes f7, the king's last way out, and stays on the long diagonal. The box is three squares. Bd5 Kd8
21… Kd8 Its only move: d8.
Play Bf7: the bishop takes e8, and the king has to go towards a8. Bf7 Kc8
22… Kc8 Its only move: c8.
Your king guards c7 and d7, so the knight can leave. Play Nc5, the fourth point of the W. Nc5 Kd8
23… Kd8 The king steps back to d8.
Play Nb7+, the last point: the W is complete, and the check sends the king back to c8. Nb7+ Kc8
24… Kc8 Back to c8, its only move.
Play Kc6: your king steps along the 6th rank, guards the knight and takes c7 and d7. Kc6 Kb8
25… Kb8 Its only move: b8.
Play Kb6, the last step: your king now stands a knight's jump from a8. Kb6 Ka8
26… Ka8 The king goes to a8, the corner of your bishop's colour.
The W is complete: f7, e5, d7, c5, b7. Your king is on b6, and the black king is in a8, the right corner.
Mate in the right corner
The knight comes back to c5 to check from a6, the bishop takes c8, and the bishop mates on the long diagonal. Watch out for stalemate.
Play Nc5: the knight heads for a6, where it will give the check. Nc5 Kb8
27… Kb8 Its only move: b8.
Play Be6: the bishop takes c8, and the king can only step between a8 and b8. Be6 Ka8
28… Ka8 Back to a8.
Na6 now is no check: the king on a8 would have no move, and that is stalemate. Wait one move with the bishop instead. Play Bd7: it still takes c8. Bd7 Kb8
29… Kb8 It has to come out to b8.
Now play Na6+: the knight checks and takes b8. Na6+ Ka8
30… Ka8 Back to a8, its only move.
Your king covers a7 and b7, the knight covers b8. Play Bc6: checkmate on the long diagonal. Any other bishop move leaves the king no move and no check. Bc6#
Checkmate in a8. The whole pattern: push the king to the dark corner, then the knight walks the W, your king walks the 6th rank beside it, and the bishop shuts the doors without a single check until the mate.
Key ideas
- Mate is only possible in a corner of the bishop's colour: a8 or h1 for a light bishop. The king runs for a dark corner. Let it, and walk it out from there.
- The knight walks a W along the edge: f7, e5, d7, c5, b7. Every jump is one file closer to the right corner, up and down between the 7th and 5th ranks.
- Your king walks the 6th rank beside the knight, f6, e6, d6, c6, b6, and never steps back.
- The bishop never gives check. It shuts the squares the king tries to slip out through and makes the waiting moves. Its only check is mate.
- The finish: your king on b6, the bishop takes c8, the knight checks from a6, and the bishop mates on the long diagonal.
Common mistakes
- Trying to mate in the dark corner: it can't be done there.
- Checking with the bishop: Bh7+ with the king on g8 just loses the bishop. The checks are the knight's job.
- Na6 with the king on a8: that is no check, and with no move left it is stalemate. Make a waiting move with the bishop first.
- Leaving the knight next to the king without your king beside it (Nd7? with the king on d8).