Mate In 3, Not 4

Logic Level 3

White to play and mate in 3. (Black plays optimally throughout.)

Give the coordinates of the landing squares of White's first, second, and third moves as a six-digit number. E.g. if White's first move was Kc1, the first two digits would be 31; if White's second move was Nd3, the third and fourth digits would be 43, and so on.

The answer is 785736.

3 solutions

Patrick Corn
May 24, 2016

Relevant wiki: Chess Puzzles - Reduced Games

I first saw this problem in Edward (not Emanuel) Lasker's excellent book Chess For Fun and Chess For Blood . It is shockingly hard to solve, given the paucity of available moves.

The key is 1 g8(N)!! and there is one variation: 1 ... b5 2 Ne7! Kxb4 3 Nc6#.

This is a beautiful example of the Indian theme .

Great problem! You should specify that black plays optimally... otherwise, there's another solution.

Mateo Matijasevick - 5 years ago

Fair enough, done.

Patrick Corn - 5 years ago

I don't understand. First, white moves its pawn to $(7,8)$ then black must move its pawn to $(2,5)$ . Then white moves its bishop to $(5,7)$ and black has no more available moves! Correct me if I'm wrong.

Christopher Boo - 5 years ago

The newly promoted knight moves to e7, allowing Black to play Kxb4.

Patrick Corn - 5 years ago

Oh now I understand. Brilliant!

Christopher Boo - 5 years ago

Brilliantly simple and simply brilliant! Thank you.

Siva Bathula - 5 years ago

took me days to find it, so many ways to do in 4

michael de seguin - 3 years, 10 months ago

Sharky Kesa
Dec 29, 2016

Lovely chess puzzle with an underpromotion.

g8=N! b5
Ne7 Kxb4
Nc6#

I would appreciate an explanation as to why queening the pawn, moving the knight, and then taking pawn with bishop is not a valid solution. I'm sure I'm missing something simple but I cannot seem to see it.

Abel McElroy - 4 years, 4 months ago

After moving the knight, Ka2 also can be played.

Sharky Kesa - 4 years, 4 months ago

thanks, I for whatever reason, did not recognize the white king as a king. thought it was a rook.

Abel McElroy - 4 years, 4 months ago

@Abel McElroy – Yeah, the pieces look a bit dodgy, but White needed to have a king and the other 2 pieces are too unlike a king.

Sharky Kesa - 4 years, 4 months ago

Zoki Kuzmanovski
Jun 16, 2018

Brilliant, very tricky not to promote to queen but to knight instead, then it all goes down like a perfect puzzle in 3 moves. With queen it is impossible to mate in fewer than 4 moves.

You mean fewer than 4 moves.

Joe Mansley - 2 years, 11 months ago

Mate In 3, Not 4

The answer is 785736.

3 solutions

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