White to move and checkmate in 4! No computer lines please.
3B4/3P4/2pkP3/2p1R3/1r3b2/1p1N1K2/n2Q2B1/3R4 w – – 0 1
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Not so difficult after all.
1. Qxf4 !
1.. Rxf4
2. Kxf4!
2…Nc3
3. Nxc5+
3…Nxd1
4. Nb7 X
2…Nc1
That’s no better.
3. Nxc5+
3… Nd3
4. Rxd3 # Or 4. Nb7#
Appendix
1. Qxf4
1…Rd4
2. Re4+
2..Kd5
3. Qe5+
3…Kc4
4. Qxc5 #
1….Nc3
2. Re4+
2..Kd5
3. Qe5 X
1.Nxf4+
I)1…Kxe5 2.Qd5+ cxd5 3.Rxd5 mate
II) 1…Rd4 2.Qa5! now a pawn move or a night move allow mate in one and in the rook moves (only along the d-file since the rook is pinned !) only 2…Rd3+ makes some sense (to avoid mate in 4 of course, not from the chessic point of view) but 3.Rxd3+ Kxe5 4.Qxc5 mate !
so there remains 2…Kxe5 but 3.Re1+! sells the matters
a)3…Kf5 4.Bh3 mate
b)3….Re4 4.Qxc5 mate!
c)3….Ke6 4.Qd7 mate !
I especially like the Qa5! move, that reminds me of the very unusual moves of Alekhine…
Too difficult.
After 1.Qxf4, black cannot prevent mate.
1… Rxf4+ 2.Kxf4 Nc3 3.Nxc5+ Nxd1 4.Nb7#
If black avoids capturing on f4, then
2.Qf8#. Other second moves for black cause mate in 3.
Sorry , I need my computer for this one.
1 Qxf4
1..Rxf4
2 Nxf4
2..Kxe5
3 Bh3
3 ..Nc3
4 Ng3# mate
1 Qxf4
1..Rxf4
2 Nxf4
2..Kxe5
3 Bh3
3 ..Nc3
4 Ng3# mate
1 Qxf4
1..Rxf4
2 Nxf4
2..Kxe5
3 Bh3
3 ..Nc3
4 Ng3# mate
Hmm, there are two solutions to it. 1. Qxf4 and ?. My comp found it, so I won’t tell you, but there is a “silent” first move that also mates in four.
I am glad someone else found more than one solution. I despise these mate in X that don’t have unique solutions. This is one reason I rarely if ever even try these when they are mates in 4 or greater- I have been burned many times.
To the anonymous commenter who wrote:
“but there is a “silent” first move that also mates in four.”
Crap on a crumb. That means there are at least 3 solutions, in my opinion. Either capture at f4 mates in 4 as far as I can tell, but neither is “silent”, which usually implies a non-capture or non-checking move. Screw it anyway, I am done with this puzzle.
Unfortunately, there are THREE solutions (i.e. different key moves). One of them is unique, the other two have several duals (i.e. different continuations for white later on – not to be confused with variations meaning there are different defenses by black).
Duals are often tolerated if the problem is strong in other regards and if the duals occur in lines of play that are subsidiary to the main theme. But here, this is definitely not true. 🙁
Ok, I think I have found the silent move the anonymous commenter described (the options for this kind of move were kind of limited by the design). I have only a partial analysis so far, but I have to skedaddle for a bit. If no one has posted it, then I will finish it later.
As I said at 8:37:00 AM CST, there is 1. Qxf4 and 1. ?, both leading to mate in four. Yes, Yancey Ward: the silent move implies a non-capture or non-checking move. I give you a hint: after 1.?,black has only ONE move that avoids mate in whites 2nd or 3rd move. It’s a pity that 1.Qxf4 is mate in four, since the silent move is a stunner. And, there are only two – 2 – correct first moves. NOT THREE.
A. E. Oslo, Norway
Dear A. E. from Oslo,
I am sorry to insist there are three solutions:
I) 1. Bb6! (thr. 2.d8=Q#) Bxe5 2.d8=Q+/Nf4+/Nxc5+ etc.
II) 1. Nxf4+! Rd4 2.Rh5/Rg5/Rf5/Qa5 etc.
III) 1. Qxf4! Rxf4+ 2.Nxf4+ Kxe5 3.Bh3 and 4.Ng6# (this is the unique and most probably the intended solution)
No, I think there are three solutions. The first two are the captures at f4 which have already been covered by the previous commenters:
1. Nf4
And there are only two responses by black here- Ke5 and Rd4. The first leads to a mate in more moves, the latter in 3 more moves:
1. …..Ke5
2. Qd6 Kf5
3. Bh3# Or
1. …..Rd4
2. Qa5
And, with the rook now pinned, and with white threatening Qc5# or Qc7#, black has only two move that extend out to 4 moves total:
2. …..Rd3
3. Rd3 Ke5
4. Qc5#
Or, white can take at f4 with the queen:
1. Qf4
With the threat of Qf8# on the next move, so black must take the queen:
1. …..Rf4
2. Nf4 Ke5
3. Bh3
To keep the black king in the net, and, now, there is no way to prevent white from mating with Ng6 on the next move. So, both captures at f4 are mates in 4 with best play by black. I spent over an hour in frustration trying to prove one of these wasn’t a solution, thus my annoyance with non-unique mate in X puzzles.
The silent move has to be
1. Bb6
Once I knew to look for it, it wasn’t hard to find- it allows the threat of d8(Q) making any pawn move by black mate on the next move; same for both knight moves; same for any rook move by black; same for the bishop moves of Be3, Bd2, Bh6, Bg3, and Bh2. So, black has only the moves Bg5 and Be5, and the first is mate in 2 more moves, and the latter is mate in 3 more moves:
1. …..Bg5
2. Qg5
And white will mate with d8(Q) on the next move on any black move that isn’t Rf4, and on Rf4, Nf4 is mate on the next move. Or
1. …..Be5
2. d8(Q)Ke6
3. Qh6 Kf7(Kf54.Qd7#; Bf6 4.Qhf6#)
4. Ne5#
Now, are there only three solutions, or can white mate in 4 with every possible first move? Just kidding.
Y. Ward, you are correct! Well done!! It’s quite amazing, but Fritz 12 does not see mate in four after 1. Nxf4, unless you choose the mate search level. On analysis level it sees 1. Nxf4 Rd4 2. Qa5 Qxe5 3.Qxc5? not 3. Re1!
This tells me that the comp after 1. Nxf4 first follows a path that leads to mate in 5, and since that’s a win!, “he” does not search for a quicker mate, just like a human would do in a real game.
Three solutions! This puzzle is a really bad one.
A. E. Oslo, Norway
Dear A. E. from Oslo,
it’s nice to see how you ignore my contribution to this … 😉
I do not write such lengthy comments as others – but I know when I am right when it comes to chess problems. I am a problemist myself.
Anon 2:02:00: Yes, I missed your “humble, but correct contribution, sorry. But Benko has taught me not to thrust problemists 🙂