No, I am not asking if a KNN vs. K can be forced if those are all that's on the board. It is well known that this is impossible.

(I wasn't quite sure om if I should have put this in here or in the Puzzling Stack Exchange, do I chose here due to their being an actual chess viewer here. I apologize in advance if my decision was wrong.)

Basically, we've all seen those puzzles where no matter what defense one side employs, they will always end up checkmated in a certain amount of moves or something.

What I'm asking here, is if anyone could make a puzzle like this, of some sort but the end result is a KNN vs. K checkmate. I would prefer if these were the only materials left in the board. Only include other material if you must. Try to keep it to a minimum though, pretty please.

Now, if there is already a puzzle if this sort, please to leave a link to it in an answer.

Here's a small composition I made, not a puzzle but a game in which Black plays terribly in an obviously winning scenario, to give an idea of what I wish to see:

[FEN "Q6b/8/4q3/1NN5/8/7r/3KN3/1k6 w - - 0 1"]

1. Qa1+ Kxa1 2. Kc2 Rc3+ 3. Nexc3 Bxc3 4. Nxc3 Qb3+ 5. Nxb3#
  • 1
    You did almost everything correct, except that there must be a blank link line between the FEN tag and the move list. – Glorfindel Mar 26 '19 at 10:56

To get the following position as a checkmate, the last move must be Nb3#.

[fen "8/8/8/8/8/1NN5/2K5/k7 b - - 0 2"]

Prior to Nb3#, black must have made a non-king move, so must have moved something to b3. If it were anything other than a pawn, it could choose to avoid the b3 square, so it's not a forced win for white. If it were a pawn on b4, it could capture the c3 knight, which is also not a forced win. Thus black must have had a pawn on c4, and be forced to capture on b3 on black's previous move.

So here's one such puzzle (LiChess):

[fen "8/8/8/8/2pN4/2N5/1PK5/k7 w - - 0 1"]

White to move and mate in 2.

It's possible to move black's pawn back a bit, and give a slightly longer puzzle with the same idea:

[fen "8/8/2p5/8/7N/2N5/1PK5/k7 w - - 0 1"]

White to move and mate in 4.

I haven't exhaustively checked all possible flips and rotations of the board (which makes more difference than I initially thought). There's also a few possible mating patterns, but I expect the idea is going to be much the same in each case.

|improve this answer|||||
  • 1
    "If it were anything other than a pawn, it could choose to avoid the b3 square,..." Is not quite correct. For instance (one of many counter examples): white Kc2, Nb3, Nc3, Nd4, black Ka1, Rb5. – user1583209 Mar 26 '19 at 15:44
  • 2
    Your #4 is cooked: 1 b3, 1 Nf3 and 1 Nf5 all work. The play after 1 b3 and 1 Nf3 has further duals, but that after 1 Nf5 is sound. – Rosie F Mar 28 '19 at 14:27

Here's a #4 where White has just KNN and there are no Black units blocking Black king flights:

[Title "C. Barton; Family Herald 5 Nov 1859, no. 65"]
[StartFlipped "0"]
[fen "8/8/8/8/8/6K1/4p1N1/4N1k1 w - - 0 1"]

1.Ne3 Kh1 2.Ng4 Kg1 3.Nf3+ Kh1 (3... Kf1 4.Ne3#/Nh2#) 4.Nf2#

Here's a #5 where White has just KNN and the play is a bit more interesting than in Barton's #4:

[Title "Otto Dehler; Denken und Raten 31 Dec 1934"]
[StartFlipped "0"]
[fen "8/1p6/8/8/3K4/N7/8/k1N5 w - - 0 1"]

1.Kc3 b6 (1...b5 2.Kc2 b4 3.Kb3 bxa3 4.Kc2 a2 5.Nb3#) 2.Kc2 b5 3.Nb1 b4 4.Nd2 b3+ 5.Ndxb3#
|improve this answer|||||


This is a real puzzle solving interface for one of the mate in 4 ideas given in another answer. There are many alternative solutions ending in 4.Nb3#

|improve this answer|||||

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.