Chess

[cinelli]

In this chess puzzle black’s king is surrounded and black’s only moves are b6 and g5. Can you find white’s sequence to mate in four moves?

Cinelli

[GrahamPlatt]

There seems to be a mate in one - nd3. So if you want to prolong the agony, just keep moving the king back and let that b pawn advance…
Oops, edit: playing in the wrong direction! Plainly nd3 and kxb. Sorry.

Nd3… kxb
Nd3-f2 ..pb6,
(If kg3, qg1 mate)
qh1 kg3
qh2 mate

[GrahamPlatt]

No. That does NOT work. N-f2 & pxn… damn. Oh, just ignore me!

[GrahamPlatt]

OK

Rc7 .. then a black pawn moves
Rc1 .. the other pawn moves.
Nd3.. kxb
Qg1 mate.

[9873210]

OK

Rc7 .. then a black pawn moves
Rc1 .. the other pawn moves.
Nd3.. kxb
Qg1 mate.

... Kh3

[mc2fool]

Lichess board setup: https://lichess.org/editor/8/1p2R3/6p1/1K2p3/4PpNp/4pP1P/4P1B1/3QN1k1_w_-_-_0_1

[GrahamPlatt]

OK

Rc7 .. then a black pawn moves
Rc1 .. the other pawn moves.
Nd3.. kxb
Qg1 mate.

... Kh3

Bugger. I did say ignore me!

[UncleEbenezer]

Bugger. I did say ignore me!

Did someone say something?

Couple of things to bear in mind with these problems:

1. It ain't chess as in a game, it's chess as in a diabolical problem space.
2. there's a gotcha (preferably several) with any obvious solution or promising line.

[CryptoPlankton]

From past experience of these, this doesn't feel right (doesn't use the rook) - so please point out why!

Spoiler:

1. Kb6 g5
2. Nd3 Kxg2
3. N(d3)f2 Kg3
4. Qg1#

[9873210]

From past experience of these, this doesn't feel right (doesn't use the rook) - so please point out why!

Spoiler:

1. Kb6 g5
2. Nd3 Kxg2
3. N(d3)f2 Kg3
4. Qg1#

3 ... P(e3)xN(f2)


now what?

perhaps:

If this were chess there is a mate in 6 with the queen taking all the e,f, and g pawns ending on e3 mate.
1. Qa1 g5 (or b6)
2. Qxe5 b6
3. Ka6 b5
4. Qxg5 b4
5. Qxf4 b3
6. Qxe3 mate

Which suggests:
1. Qd8 g5 (or b6)
2. Rd7 b6
3. Rd2 p(e3)xR(d2)
4. Qd4 mate

[CryptoPlankton]

From past experience of these, this doesn't feel right (doesn't use the rook) - so please point out why!

Spoiler:

1. Kb6 g5
2. Nd3 Kxg2
3. N(d3)f2 Kg3
4. Qg1#

3 ... P(e3)xN(f2)


now what?

perhaps:

If this were chess there is a mate in 6 with the queen taking all the e,f, and g pawns ending on e3 mate.
1. Qa1 g5 (or b6)
2. Qxe5 b6
3. Ka6 b5
4. Qxg5 b4
5. Qxf4 b3
6. Qxe3 mate

Which suggests:
1. Qd8 g5 (or b6)
2. Rd7 b6
3. Rd2 p(e3)xR(d2)
4. Qd4 mate

Thank you! Not sure what all the "mate in six" preamble was about, but I like the solution.

I'll blame COVID (fifth day) this time!

CP

[9873210]

From past experience of these, this doesn't feel right (doesn't use the rook) - so please point out why!

Spoiler:

1. Kb6 g5
2. Nd3 Kxg2
3. N(d3)f2 Kg3
4. Qg1#

3 ... P(e3)xN(f2)


now what?

perhaps:

If this were chess there is a mate in 6 with the queen taking all the e,f, and g pawns ending on e3 mate.
1. Qa1 g5 (or b6)
2. Qxe5 b6
3. Ka6 b5
4. Qxg5 b4
5. Qxf4 b3
6. Qxe3 mate

Which suggests:
1. Qd8 g5 (or b6)
2. Rd7 b6
3. Rd2 p(e3)xR(d2)
4. Qd4 mate

Thank you! Not sure what all the "mate in six" preamble was about, but I like the solution.

I'll blame COVID (fifth day) this time!

CP

It's how I would play this position in a real game, particularly if I had time trouble. When I wrote that I did not have the answer. The mate in 6 showed me how to use the queen and I stumbled into the mate in 4. Some people may be interested in the thought process rather than just the answer.

[mc2fool]

Which suggests:
1. Qd8 g5 (or b6)
2. Rd7 b6
3. Rd2 p(e3)xR(d2)
4. Qd4 mate

Close, but 4. Qd4 e5xQ !

[9873210]

Which suggests:
1. Qd8 g5 (or b6)
2. Rd7 b6
3. Rd2 p(e3)xR(d2)
4. Qd4 mate

Close, but 4. Qd4 e5xQ !

Rats, 4. Qxb6 mate mate in 6 was so much easier.

[GoSeigen]

Simplistic, but does this work?

Spoiler:

1. Rc7 ...
2. Rc1 ...
3. Nd3+ KxB
4. Qg1 mate


GS

[mc2fool]

Simplistic, but does this work?

Spoiler:

1. Rc7 ...
2. Rc1 ...
3. Nd3+ KxB
4. Qg1 mate


GS

Nope. 4. Qg1 Kxh3

[GoSeigen]

Simplistic, but does this work?

Spoiler:

1. Rc7 ...
2. Rc1 ...
3. Nd3+ KxB
4. Qg1 mate


GS

Nope. 4. Qg1 Kxh3

Aargh. Cunning puzzle.

GS

[cinelli]

The solution:

The prize goes to 9873210 for the correct solution:

1 Qd8! b6 or g5
2 Rd7! g5 or b6
3 Rd2! exd2
4 Qxb6 mate

I think the rook sacrifice is brilliant as it not only gives black a move, it also frees the diagonal from b3 to the king. This is a problem by Fritz Giegold.

Cinelli