KNF v K

The makruk endgame KNF v K is surprisingly tough, and one of the fundamental endgames to learn.

I use here a mix of fairy chess conventions and translated Cambodian names for the pieces: khun (king, K for king), neang (queen, Q for queen), tuuk (boat, R for rook), sey (horse, N for knight), khon (S for silver general), trey (fish, F for ferz).

(The convention in endgames is that the superior side is white; in this case the side with horse and fish.)

Result

The result is generally a draw, although in more than a few cases white can trap the black king in “the wrong corner” (from the defender’s point of view) and win.

Mating position

To begin understanding this endgame, first we need to see white’s main winning idea. Consider the following position.

From the diagram, play proceeds 1.Nh3 Kh2 2.Ng1 Kh1 3.Fg2+ Kh2 4.Nf3#.

This sequence is important, so please make sure to remember it. There are several important remarks to make here:

• The mate can only be accomplished in the “wrong” corner, one which the fish can reach. (In western chess, this is analogous to the KNB v K mate.)
• White keeps black trapped in the corner with king and knight or fish, repositioning them one at a time for the mate.
• If in the first diagram it were black to move instead, the sequence above doesn’t work directly (wrong side to move; a parity problem!)

The last point is interesting. Unlike the western chess KNB v K endgame, white cannot lose a move with the horse or the fish. Instead to regain the mating sequence, white must triangulate with the king to lose a move.

Parity

Consider the first position, but with black to move instead. 1…Kh2 is forced; now what?

White needs to lose a move with the king, but currently he’s busy guarding g3. First let’s keep g2 guarded while giving him the f3 square to use; 2.Fg4 Kh1 3.Fh3 Kh2 4.Kf3!.

Now black can choose a square to run to, but white will get the correct parity with the king eventually. Let’s say 4…Kh1 5.Ke2! (we see why the fish guards g2) 5…Kg1 6.Ke1! zugzwang.

Whichever square black’s king goes to, white chooses the correct option for their own king to have the correct parity. If 6…Kh2 7.Kf2!, or else: 6…Kh1 7.Kf1! Kh2 8.Kf2 Kh1 9.Ne6 Kh2 10.Ng4 Kh1 and now we can do the winning sequence: 11.Fg2+ Kh2 12.Nf3#.

Parity plays a large role in this endgame, and calculation is needed to determine which parity is desired at a critical moment – see move 7.

Proper defense

Despite the existence of the mating pattern, black can usually draw KNF v K. The correct drawing technique is to head to one of the “correct” corners. If forced away, black should immediately head to the other “correct” corner.