Wednesday, August 13, 2014

Brilliant endgame tactic

White to move and win.



Yancey Ward said...

Tricky after the first 4 moves, but I think everyone should get this one since the first four moves literally play themselves. After that, you have to spot the potential pin on the bishop and work out how to avoid stalemating black in the key lines.

1. Bd7 Bb3 (Bc2 and Bd1 below)
2. e7 Bf7 (what else?)
3. Kf6 Bh5 (again, what else?)
4. Kg5 Bf7 (again, what else?)
5. Kh6!

Setting up zugzwang. Black can't safely move the bishop without allowing the pawn to queen. If black plays Kg8, white just pins the bishop with 6.Be6 and mate will follow quickly since the pawn will queen now with check. This leaves only the pawn moves, but white is waiting to enforce the zugzwang anyway:

5. .....a6 (a5 6.Ba4 as below)
6. Bc6!

Pretty sure this is the only winning move. If white tries a careless 7.Ba4, black has a5: [7.Ba4? a5 8.Bd7 a4! 9.Ba4 Kg8 10.Bb3 Kh8! and the pin no longer works since white can't take the bishop without stalemating black!]. Continuing:

7. .....a5 (what else now?)
8. Ba4 and now black must either give up his bishop, move the bishop off the h5/e8 diagonal, or he must allow white to pin the bishop by playing Kg8 when the stalemate won't work since black will still have a pawn to move.

Finally, at move 1, the other bishop moves won't save black:

1. Bd7 Bc2
2. Kf6!

An only move to win for sure. Continuing:

2. .....Bd1 (what else- plans Bh5)
3. e7

Or Kg5. Continuing:

3. .....Bh5
4. Kg5 and we have transposed to the previous line.


1. Bd7 Bd1
2. e7 Bh5
3. Kg5 with another transposition.

Anonymous said...

I haven't been able to solve it but I see some ideas emerge from the sample line 1. Bd7 Bb3 (not forced however, one of a few possible moves), 2. e7 Bf7, 3. Kf6 Bh5

The idea here is that Black is in a near zugzwang as far as his King and Bishop are concerned. Obviously the Bishop has to stay on the diagonal to keep the pawn from successfully queening. But h5 is the only square where it isn't simply en prise. Meanwhile Black's King only has two light squares which he can go to, but then White would have a check with his Bishop which would give him the tempo to then bring the Bishop to the crucial diagonal and block Black's coverage of the Queening Square.

For example, let's pretend Black doesn't have the a-pawn or for some reason he can't move it. Then,
4. Bc6 .... or Bb5 or Ba4, the idea is the same
.... Kh7
5. Be4+ Kg8
6. Bg6 .... And the Bishop interposes itself between Black's Bishop and the queening square. Exactly the same thing happens if Black varies on move 4 with ....Kg8, 5. Bd5+ followed by Bf7. Black can't stop the Pawn from queening.

But if Black can't move either King or Bishop, then he can only move his a-pawn. Can't White simply shuffle his Bishop along the a4-d7 diagonal until the a-pawn gets to a4 when White simply captures the Bishop and now Black is fully in zugzwang?

I have to conclude White wins this way upon 1... Bb3. The question is, is there a similar win on other Black 1st moves such as ...Bc2+ or ...Bd1?

...Bb3 variation:
1. Bd7 Bb3
2. e7 .... Obviously forced. White can't allow Black to sac the Bishop to eliminate his only pawn.
.... Bf7 Also forced, Black must be prepared to capture if the pawn queens at e8
3. Kf6 Bh5 Only square. If ...Kg8, 4. Bd6! pins the Bishop, preventing it from shuffling along the diagonal with the queening square. And if 4... Bxd6, 5. e8=Q+ wins
4. Bc6 a6 Black has no moves with either King or Bishop for the reasons given above.
5. Bd7 a5
6. Bc6 a4
7. Bxa4 ... Zugzwang. White wins.

- Craigaroo

Anonymous said...

kg6 trapping the king!!!!

.... B checks
Kh6 B attacks W pawn
W pawn advances B moves to f7 to stop pawn
Ba6 bloxking B pawn and Black in Zuggy :)))

Must be the corrrect answer since several people found the solution funny.

PROF.S.G.BHAT said...

1.Bd7 Bb3
2.e7 Bf7
3.Kf6 Bh5
4.Bf5 Be8
5.Bg6 Bb5
6.Kf7 Bc6
7.Kf8 a5
8.Be8 Bf3
9.Bd7 Bh5
10.Be6 a4
Now black having lost control of e8 white queens and wins.Even if black plays differently at 2nd move or so result is no different.

Harry Hariharan said...

This is a monster of a problem!
Half way through the solution I have is
>>A1-2...Bxd7.3.exd7 and 4.d8=Q wins
>>A2-2...Bb5/c6.3.Bxb5/c6. and 4.e7. and 5.e8=Q wins
>>A3-2...Bb3.3.e7.Bf7.4.Be6! and 5.e8=Q wins.
>>A4-2...Bc2.3.e7.Bg6.4.Kxg6. and 5.e8=Q wins
>>>A51-4...Bf7.5.e8=Q+ wins.
>>>A52-4...Kh7/8.5.Bf7.Bxf7.6.Kxf7. and 7.e8=Q wins.

>>B1-2...Bxd7.3.exd7 and 4.d8=Q wins
>>B2-2...Bb5/c6.3.Bxb5/c6. and 4.e7. and 5.e8=Q wins
>>B3-2...Bb3.3.e7.Bf7.4.Kxf7 and 5.e8=Q wins.
>>B4-2...Bc2.3.e7.Bg6.4.Bf5!. and 5.e8=Q wins
>>>B51-4...Bg6.5.e8=Q wins.
>>>B52-4...Kg/h8.5.Bg6!.Bxg6.6.Kxg6. and 7.e8=Q #

>>C1-7...Bxe8.8.Kxe8 and 9.Kd8. and 10.e8=Q wins
>>C2-7...Bb5/c6/d7.8.Bxb5/c6/d7. and 9.e8=Q wins
>>C3-7...Bb3.8.Bd7.Bf7.9.Kxf7 and 10.e8=Q wins.
>>C4-7...Bc2.8.Be7.Bg6.9.Be6!.Bh5.10.Bf7.Bxf7.11.Kxf7. and 12.e8=Q wins
>>C5-7...Bd1.8.Bd7.Bh5.9.Be6.Bg6.10.Bf7.Bxf7.11.Kxf7. and 12.e8=Q wins.

Based on above, I am sure for other black replies, the solution would transpose into one of above variations. Interestingly black king cannot go to g8 or h7 white squares as the white color bishop will eventually get pinned against it or be lost through zugzwang!

Enough for now.


Anonymous said...

I missed something for Black in my analysis.
1. Bd7 Bb3
2. e7 Bf7
3. Kf6 Bh4
4. Bc6 Kh7 I thought Black couldn't expose his King to check because it would allow White to take control of the key diagonal.
5. Be4+ Kh6 I missed this. Black prevents Bg6 which would allow White to Queen. So my idea doesn't seem to work. :-(

Yancey Ward said...

Prof. S.G,

That looks ok to me right now. At least, I can't poke holes in your solution yet, and I have been studying it for 30 minutes. There are variations, however, I have not gone into just because they look trivial, but maybe I miss something.

Yancey Ward said...


I think you are overlooking Black's drawing chances. I will take one line in particular since it is similar to ones I have encountered in the past:

1. Kf6 Bb3
2. e7 Ba4
3. Kf7

Of course, the idea behind this line is to take control of the e8 square with the king, ala Prof. Bhat's solution above. However, in your line there is small problem:

3. .....Bb5
4. Kf8 Kh7!

This may, or may not, be the only move for black, but it accomplishes a key defensive repositioning for black. As things stand, white must bring the bishop to e8 to force the black bishop away, and this can only be done by maneuvering the bishop over to the h5/e8 diagonal. Black's king is moving to make that ineffective (black can't prevent it, but he can make it pointless by making sure white can only ever oppose the bishops on e8, costing white a tempo).

5. Be6 Kg6 (Kh6 probably ok)
6. Bf7 Kf6 (Kg5 ok, too)
7. Be8 Be2 (Bd3 and Bc4 good too)
8. Bd7 Bh5

And the black bishop will just transport to the other diagonal in two moves whenever the white bishop is on e8. I don't think there are any variations in the above where white can win this after the first move. I have played these sorts of endings over the board dozens of times from both sides, and I have studied them after the games, too, and including studying endings like this as puzzles. This is a common drawing line in such circumstances. If you can find a potential hole in the above, I will be willing to address it.

PROF.S.G.BHAT said...

Dear yancey,
Your solution is really thrilling with zugzwang etc. which I had never imagined.My solution is pedestrian to say the least.

Anonymous said...

It's pretty clear through all analysis given here, that by posotioning the K on h6 and of course starting with Bd7, black can be pushed into zugzwang. All he has left is his a-pawn.
But....! The a-pawn cannot be taken! It has to be blocked.
For all those who take the a-pawn with Bxa4, it's a draw! Therefor, white must understand he has to make a quiet move with his B if a7-a6-a5 is played. If a7-a5 is played, he plays Ba4.
Very very tricky and subtle!