Rook and King vs. Knight and King
Concepts
The rook vs. knight endgame can be drawish, if the knight is able to get close to his king. Yet if the player with the rook is able to keep them separated, it is an interesting, and definite win. This is a difficult endgame, and while not as tricky as queen vs rook I would say it is harder than the bishop and knight vs a lone king.
This endgame is very subtle. The superior side has to understand knight movement very well to avoid a draw.
There are three main principles to these positions, and both involve manipulating the knight's movement so that it can be captured and reduced to a won rook ending:
- Move the knight into the corner, or up against the wall.
The idea here is simple. Against a wall, or better yet, in a corner, the knight has fewer squares which it can flee to, and your job of taking those squares away becomes much simpler.
- The king can also close on the knight, making the knight's escape possible, and ensuring a draw
Don't forget about that damned king! Keep him far away and threaten mate if he gets too uppity.
- If possible, a skewer of the king and knight saves a lot of time.
This should be fairly easy to anyone with basic tactical knowledge of chess. Lining up the knight and king where the king cannot defend the knight and the rook can either pin or check simplifies this position greatly.
Annotated Example
+---+---+---+---+---+---+---+---+
| | | | |BN | | | | 8
+---+---+---+---+---+---+---+---+
| | | | | | | | | 7
+---+---+---+---+---+---+---+---+
| | | | | | | | | 6
+---+---+---+---+---+---+---+---+
| | | | | | | | | 5
+---+---+---+---+---+---+---+---+
| | | |WK | | | | | 4
+---+---+---+---+---+---+---+---+
| | | | | | |WR | | 3
+---+---+---+---+---+---+---+---+
| | | | | | | | | 2
+---+---+---+---+---+---+---+---+
| | | |BK | | | | | 1
+---+---+---+---+---+---+---+---+
A B C D E F G H
Here we see a basic example of this position. The knight is already in a fairly bad place, and is terribly far away from the king. White can win this if he traps the errant knight.
1. Rg6
Taking away the d6 and f6 squares from the knight.
1. ... Nc7 2. Kc5
Further restricting the knight, who can now only flee to his starting square or the corner at a8.
2. ... Kd2
2. ... Na8 loses to 3. Kb7 taking the last of the escape squares away. Similarly, 2. Ne8 loses to Kc6 for the same reason.
3. Rc6
Forcing the issue.
3. ... Ne8 4. Kd5
Bringing the king toward the corner.
4. ... Ng7 5. Ke5
Guarding against Nf5, which draws.
5. Ke3 6. Rh6
Forcing the knight to jump back to e8. (Any king move would lose the knight to7. Rh8!)
6. ... Ne8 7. Rh7
This is the end of the road for the black knight. No more shall he say such things as "None shall pass." The final liberties have been removed, and as a go player might say, the knight is in atari. Now all that remains is for the white king to clean up.
7. ... Kd3 8. Ke6 Kd4 9. Re7 Nf6 10. Kxf6 1-0