Sunday, July 07, 2013

Brilliant tactic

White to move and win. How should white proceed?



Yancey Ward said...

This is a tough one. Obviously, white would like to put the queen on f6 and go for the mate, but black's threat on b2 stalls this idea:

1. Qf6? Qb2 (the only save??)
2. Kd2 Rbd8

It matters which rook black checks with since there is a potential skewer: [2. ...Rfd8? 3.Ke3 Rd1 4.Rd1 gh5 5.Rb1! should be decisive]. Continuing:

3. Ke3 Rd1 (what better?)
4. Rd1

White doesn't have time for 4.h6 since black will check from c1 followed eventually by a check from f1/f3 to liquidate the queen at f6. Continuing:

4. .....gh5 (Qb6 any better?)
5. Rh1

Maybe 5.g6 is beter, but I am not quite seeing it. Continuing:

5. .....Qc2 (any better move?)
6. Rh5 Qd3
7. Kf4 Qf1
8. Ke5 Qf6 (any better move?)
9. gf6 and I don't really know who is better here, but it looks close to even to me since black will have a hard time dealing with the threat of draw by repetition should white go for it.

So, can white preemptively block the rook check from d8 above by playing 1.Rd4? Let's see where this leads:

1. Rd4 Qb2 (any better move?)
2. Kd2 Rfd8 (better R this time)
3. Qf6

So, white finds the time for Qf6. Continuing:

3. .....Rd4
4. Qe3

Forced by the threat on the c3 knight. Continuing:

4. .....Qb6

I looked a long time. I can't find better move. Black needs to get at the white king ASAP, and the black queen can do this from b6-f2. Continuing:

5. Qf6

I think white retains a good edge with 5.Qxc4, but this looks just slightly better. Continuing:

5. .....Qc5 (threatening Qd6+)
6. hg6 Qd6 (forced)
7. Nd5! Qf6 (forced)
8. Nf6 and white clearly stands better, but is it decisive?

So, let's back up the move 5 for white- should he take the bishop?

5. Qc4 Qf2 (better move?)
6. Qe2! Qg3 (again, better?)

And, sure, white stands better materially, but his king is a problem. I am not even sure that he can avoid a draw by repetition here.

Basically, I give up. Will just look the game up and see what Karjakin actually played.

Yancey Ward said...

Well, that was interesting. Karjakin played 1.Rd4, but Hao put the rook I thought was good on d8 after taking at b2.

In any case, the chessbomb engine suggests that 1.Na4 was the best move. It protects b2 and if the queen takes at a4, she is out of position for a move.

Knyt4k said...

1. Na4 Qxa4
2. Qf6 (and Black is defenseless against the imminent mate on g7 or h8.

Lorfa said...

What a nightmare.

I considered Na4, with the purpose of getting my queen to f6, then I rejected that because I could play Qf6 immediately.

My line went 1. Qf6 Qxb2+ 2. Kd2 Rbd8+ 3. Ke1 Rxd1+ 4. Kxd1 Qa1+ 5. Kd2 Qxh1 6. h6 Qg2+ 7. Kc1

Here I thought I've got him, after 7..Qg1+ 8. Nd1 he's toast.

I missed the simple 7..Qf1+ ruining everything and winning for black.

There are other similar variations, but 3. Ke1 seems to be losing and 3. Ke3 seems to be drawing.

I don't know how to reject a seductive move like Qf6 over the board. Maybe I'm holding on too tight to the idea of the mate.

Craig Johannsen said...

[FEN "1r3rk1/p1p2p2/2p3p1/6PP/1qb1PQ2/2N5/PPP5/2KR3R w - - 0 0"]

My initial move was Na4 to prevent Qxb2. The following analysis was developed using Fritz 13 in infinite analysis mode. Actual gameplay by Karjakin and Wang Hao is presented after that. It seems to me that Na4 is better than Karjakin's Rd4, based on the following lines.
1. Na4 Qe7
2. Qh4 Kg7
3. hxg6

(3. Qg3 Rbd8
4. Rxd8 Rxd8
5. h6+ Kh7
6. Qc3 Qxg5+
7. Kb1 Bxa2+
8. Kxa2 Rg8
9. Nc5 Qd8
10. Kb1 Qe7
11. e5 g5
12. Ne4 Rg6
13. Rf1 Rxh6
14. Rxf7+ Qxf7
15. Nxg5+ Kg6
16. Nxf7 {White has a decisive advantage.}
16... Kxf7
17. Qd4 Re6
18. Qxa7 Re7
19. Qf2+ Ke6
20. Qf6+ Kd7
21. Qf5+ Re6
22. b4 Ke7
23. Kb2 c5
24. b5 Rb6
25. Kc3 Re6
26. Kc4 Rb6
27. Qc8 Rh6
28. Qxc7+ Ke8
29. Kxc5 Rh2
30. c4 Rd2
31. b6 Rd7
32. e6 Rxc7+
33. bxc7 Ke7
34. c8=Q Kf6
35. Qd7 Kf5
36. e7+ Kg6
37. e8=Q+ Kf6
38. Qee7+ Kg6
39. Qg4+ Kh6
40. Qgg5#)

3... Rh8
4. Qf4 Kxg6
5. Rh6+ Rxh6
6. Qf5+ Kg7
7. gxh6+ Kh8
8. Rg1 Qh4
9. Qe5+ f6
10. Qxc7 Qxh6+
11. Kb1 Rg8
12. Qxa7 Bb5
13. Nc3 Rxg1+
14. Qxg1 Qh3
15. a4 Bc4
16. a5 Qh5
17. b3 Qxa5
18. Qh2+ Kg7
19. Qg3+ Kf7
20. bxc4 Qb4+
21. Kc1 Qxc4
22. Qd3 Qxd3
23. cxd3 Ke6
24. Kd2 {Black should resign.}
24... Ke5
25. Ke3 Kd6

(25... c5
26. Na4 Kd6
27. Kf4 Ke7
28. Nxc5 Kf7
29. d4 Kf8
30. e5 Kf7
31. exf6 Kxf6
32. Ke4 Kg5
33. Ke5 Kg6
34. Ne6 Kh6
35. d5 Kg6
36. d6 Kh5
37. d7 Kg4
38. d8=Q)

(25... f5
26. Na4 Kd6
27. Kf4 fxe4
28. dxe4 Kd7
29. e5 Ke6
30. Nc5+ Kd5
31. e6 Kxc5
32. e7 Kb4
33. e8=Q)

26. Kf4

(26. Kd4 Kd7
27. Kc5 Ke6
28. Kxc6 Ke5
29. Ne2 f5
30. exf5 Kxf5
31. d4 Ke6
32. d5+ Ke7
33. d6+ Kd8
34. d7 Ke7
35. Kc7 Ke6
36. d8=Q)

26... Kc5
27. Na4+ Kb4
28. Kf5 Kxa4
29. Kxf6 Kb4
30. e5 Kb5
31. e6 c5
32. e7 Kb4
33. e8=Q Kc3 {Black truly doomed.}

Actual gameplay:
1. Rd4 Qxb2+
2. Kd2 Rfd8
3. Qf6 Rxd4+
4. Qxd4 Qb6
5. Qxc4 Rd8+
6. Kc1 Rd4
7. Qe2 Qc5
8. Nb1 Qxg5+
9. Nd2 {Black resigned. Not sure why. White's advantage not that overwhelming as far as I can determine.}

Playing out remainder of game using Fritz 13 in infinite analysis mode:
9... gxh5
10. Rxh5 Qg3
11. Rf5 Qa3+
12. Kb1 Qb4+
13. Nb3 Rd6
14. Qf3 Qc4
15. Rh5 Kf8
16. Qg4 Qe6
17. Rh8+ Ke7
18. Qg8 Rd1+
19. Nc1 c5
20. Qe8+ Kd6
21. Qd8+ Kc6
22. Qxd1 {White has a decisive advantage.}

CraigB said...

I like 1. Na4. This guards b2, and Black is ill-advised to capture the N because that would allow 2. Qf6 (also guarding b2 and, more importantly, threatening 3. hg and 4. Rh8#).

Black has numerous ways to defend against Qf6, but they all require him to abandon his attack on b2 and white's attack on g7/h7/h8 can continue in various ways.

rocketboy onicc said...

I wonder if 1.Na4 is enough to try to deflect the Queen from the long diagonal? If 1...Qxa4 when 2.Qf6 (or maybe 2.hxg6 first) looks very strong. Does it win?
Instead, maybe Black can play 1...Qe7 and I'm not sure who's really better. White's attack seems just a touch slow.
Rd4 is the only other option I can see, but it looks very scary. b3 just looks to be losing. Qf6 is a worse version of Na4. What else is there?