White to move. How should white proceed?
A Stamma classic
1kb4r/pp4r1/1P2n3/1N2N2q/4p1p1/R1QpPpP1/R2P1P2/6K1 w – – 0 1
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Black’s particular mate threat means everything white does must be with check, capture the queen, or divert the h8 rook or the queen from the h-file. Let’s look at the starting checks.
I think I can eliminate ba7 pretty quickly:
1. ba7 Ka8
And, now, there is only Qc8 and Nc7 check left, but neither lead anywhere:
2. Nc7 Nc7 and white is out of checks. Or, more interesting:
2. Qc8 Rc8
And, even though the rook was diverted, black is still threatening mate, but with Rc1, now. All white has are delaying moves other than the move Ra1 protecting the back rank, but on that, black will return the rook to h8 and mate soon afterward.
I also don’t think Qc8 will work:
1. Qc8 Rc8 (Kc8 probably ok, too)
2. ba7
The only way this is really different from the previous line (other than the worthless knight checks from d7 and c6):
2. …..Ka8 and this is almost identical to the previous line starting with ba7.
Or
1. Qc7 Rc7
2. bc7 Ka8 with no checks left, or
2. Nd7 Rd7
3. ba7 Ka8
4. Nc7 Rc7 with no check left for white.
Finally, we are left with the two knight checks from c6 or d7. They have the added benefit of opening up the d5-g7 diagonal for the white queen, which we will see is critical in one of the lines:
1. Nc6 bc6 (Ka8 2.Ra7#)
2. ba7 Ka8 (Kb7 3.a8Q Kb6 4.Qcc6#)
And, no matter how white plays this, black will take the knight if it checks from c7, or block the check if white plays Qc6. At the end, white will run out of checks and be mated one way or another. Or
2. Qe5 Qe5 (only winning move)
Finally, white isn’t facing mate on the next move, and has time for something other than another checking move, but every attempt is just a bit too slow:
3. ba7 Ka8
4. Nc7 Qc7 and it is over. Or
3. Na7 Bb7
4. Nc6 Bc6 and with the guard on a8 and b7 by the bishop, white will soon be out of checks once again. Or
3. Ra7 Ra7
4. Na7 Bb7 and like before, white will soon run out of checks. Or
3. Rb3 Qb5!
4. Rb5 cb5 and there is nothing here for white.
So, by process of elimination, the right move must be what is left:
1. Nd7 Rd7 (Ka8 2.Ra7#)
2. Qe5!
I am pretty sure Qh8 wins, too, based on the line with Qe5:
2. …..Qe5
On Nd7 or Rd7 white just captures with the pawn and mates soon after since Ka8 is met with Ra7#, and the capture at c7 is met by Qc7 followed by mate. In any case, we now have the situation where white isn’t facing an immediate mate, and now has time to play another move other than a check. The way this position is different from the previous line that started with Nc6 is that black has no way to cover a8 with the bishop or his queen- the b7 pawn betrays his liege:
3. Ra7
And all black has now are delaying tactics like Nc7, but white just captures with the knight and then plays Ra8, or sacrificial delays like Rh1 and/or Qg3:
3. …..Qg3
The only interesting delay:
4. fg3 f2 (Rh1 no different)
5. Kf2 Rf7 (Rh2 6.Kg1)
6. Kg1 and it is black that will soon run out of checks and get mated.
Back at move 1, it does black no good to capture with the bishop at move 1, though it does play a bit differently:
1. Nd7 Bd7
2. Qc7
I spent a bit of time in the rabbit hole of trying to make Qe5 work, but black captures at e5 with the queen, and on 3.Ra7, simply plays the king to c8 opening the b8 square for his queen to block the check of Ra8: [ 2.Qe5 Qe5 3.Ra7 Kc8! 4.Ra8 Qb8 5.Na7 Kd8 6.Rb8 Ke7 7.Rh8 and I think white is clearly better with the exchange, but it isn’t the hammer blow that problems like this usually require]. Continuing:
2. …..Nc7 (again, Ka8 3.Ra7#)
3. ba7! Kc8 (Ka8 4.Nc7#)
4. a8(Q)Na8
5. Ra8#
That was an excellent analysis. I could only find a solution with Nc7 Bxc7 and I was still searching for Nc7 Rxc7.
Oops sorry. I saw the solution only for Nxd7 Bxd7 and I couldn’t find the solution for Nxd7 Rxd7
1Qc7+ Wins
1, Nd7+ Bxd7 (or Rxd7)
2. Qe5+ QxQ
3. Rxa7
and there is no defense for 4. Ra8#
if
1. Nd7+ Bxd7
2. Qe5+ Kc8
3. QxQ RxQ
4. bxa7 Bxb5
5. a8=Q+ Kc7
6. Qa5+
1-0
1.Ned7+ Bxd7
2.Qe5+ Qxe5
3.Rxa7 Nc7
4.bxc7+ Qxc7
5.Ra8#
– High skill from MR KO (Malaysian)
Hi Yancey,
you wrote:
I am pretty sure Qh8 wins, too, based on the line with Qe5:
2. …..Qe5
On Nd7 or Rd7 white just captures with the pawn and mates soon after since Ka8 is met with Ra7#, and the capture at c7 is met by Qc7 followed by mate.
ain´t it true, that c7 is still covered 3 times and being attacked three times? so this line would still end in white losing the queen, wouldn´t it?
2. … Nc7
3. bxc7+ Rxc7
4. Qxc7+ Kxc7
interesting enough, that the queen can force its way to e5. but i still can´t see a way to checkmate black! that´s annoying. maybe your suggested move 2. Qxh8 is the best variation?
greets, jan
I would say: 1) Nd7+ and now:
Bxd7, Qc7+ – Nxc7, bxa+ – Kc8 (Ka8, Nxc7++), a8Q+ – Nxa8, Rxa8++
or:
Rxd7, Qxh8 – Qxh8, Rxa7 with a small threat of mate on a8! 🙂
Phew, took some time to find that…
It is clear that Rxa7 would be a winning move, if only there was time for it. To win the necessary tempo, I think white has to deflect black queen from h-file, this can be done by a queen sack:
1. Nd7+ Rxd7
2. Qe5+ Qxe5
3. Rxa7 Nc7
4. bxc7 Qxc7
5. Ra8#
or
2. … Nc7
3. Qxc7+ Rxc7
4. bxc7+ Ka8
5. Rxa7#
1.Qc7+ and 2.b:c7+ and 3.R:a7++
Yancy’s analysis is mind blowing.However I learnt one thing from him, either keepon giving checks or eliminate mating threat by black. hence my moves
1 Nd7+
(a)1 …. Bxd7
2Qc7+ Nxc7
3 bxa7+ Ka8
4 Nxc7#
(b)1 ….. Rxd7 here blck controls c7 twice and Q sac does not give result. Hence
2 Qxh8 eliminating mate threats for a while.
2….. Qxh8
3 Rxa7 no check now but mate by Ra8 next move.
Jan,
You are forgetting the knight at b5 covers the queen after Qxc7, which is the sort of thing I do all the time when playing- not noticing knights.