|
< Earlier Kibitzing · PAGE 2 OF 3 ·
Later Kibitzing> |
| Jul-10-09 | | zooter: hey, Not bad, I got it right till where black resigned! :) Just yesterday on FICS I sacrificed a knight for 2 pawns and a strong attack and won within 20 moves.... So, I guess we need to take some risks from time to time |
|
Jul-10-09
 | | al wazir: Strange. The redoubtable <dzechiel> was stumped on this puzzle? I found moves 15--17 (the ones leading to black's resignation) in seconds. Finding the moves is one thing, of course, while proving that they lead to a forced win is something else. If 17...Kd7 then 18. Qxf7+ Kc8 19. Rc1+ obviously wins outright. Less obviously, 17...Be7 18. Rxe7+ Kxe7 19. Re1+ also wins; white can recover a ♖ by means of a double threat with his ♕. White always ends up at least two ♙s up after 10 moves or so. But I didn't analyze all these complications before peeking. So would I have played this line OTB? Against a GM? In a money game? I dunno. |
|
| Jul-10-09 | | Keith Dow: Dear dzechiel,
Your analysis is correct.
After:
22 Qxd8+ Kg7
23 Re8
Either:
23 ... Qxe8
24 Qxe8
And white has a large material advantage.
23 ... h6 Mate in 13
23 ... Kg6 Mate in 6
23 ... Whatever Mate in 6 moves or less. |
|
| Jul-10-09 | | kdogg the patzer: How about this continuation?
17... Be7, 18. Re1
Now 18... Rd7 and 18... Qd7 seem to fail to 19. Rf6. The best defense seems to be 18... Qb4, which prevents Rf6 because of the threat of back rank mate. I think the simple 19. Re2 does the trick (19... Rd7 20. Rf6). Unless I'm missing something, in all cases, white winds up the exchange, plus a pawn, with strong pressure on black. Did I miscalculate? |
|
| Jul-10-09 | | ROADDOG: Blacks position would require the wizardry of Jakovenko (and the play with white of Naiditsch) to pull this one off. Cant get todays game out of my head. |
|
Jul-10-09
 | | Jimfromprovidence: If 15…a6, white can of course retreat the knight, but 16 Nxf7 still works (seeing Nxd8).
click for larger viewWhite will get black's rook on d8 after 16 Rg6.
If black tries something different, for example, if 16…Rxf7?!, then 17 Rxe6+ Qxe6 18 Nc7+ nicely wins the queen (because of the pinned rook).
click for larger view |
|
| Jul-10-09 | | Summerfruit: Black is a pawn up.
Black's king is stuck in the center, which suggests a sacrificial attack starting with: 15.Nxb5! Qxb5 16.Nxf7!
Now 17.Nd6++ is threatened as well as 17.Nxd8+ and 17.Rxe6+, so black is forced to capture the knight: 16...Rxf7 17.Rxe6+
Black must intervene with the bishop, since 17...Kd7 allows 18.Qxf7+ continuing the attack with material advantage. 17...Be7 18.Rxe7+! Kxe7 19.Re1+
Now 19...Kd7 or 19...Kd6 allows 20.Qxf7(+), and the attack continues with material advantage. That leaves a) 19...Kf6 20.Qxf6+ Kf5 21.Re5+ Kg4 22.h3# (or Qg5#) b) 19...Kf8 20.Qxh6+
We have the following alternatives:
b1: 20...Rg7 21.Qf6+ and the rook at d8 is captured with a check next move, white is winning b2: 20...Kg8 21.Qg5+ and the rook at d8 is captured with a check next move, white is winning |
|
| Jul-10-09 | | johnlspouge: Friday (Difficult):
Grischuk vs Bareev, 2001 (15.?) White to play and win.
Material: 2N for 2B+P. The Black Ke8 has 1 legal move, e7. The Black Rg7 has the absolute burden of preventing Qh5xf7#. The White Re1 faces Ke8, separated by Ne5 and Pe6, suggesting a clearance, with Re1 capturing Pe6 or pinning Pe6 to Ke8. The White Qh5 pins Pf7 to Ke8, so only Qb6 protects Pe6. The Black Qb6 can therefore be overloaded by 15.Nxb5. The White Nc3 also attacks Pd5, whose protection from Pe6 might be illusory. The White Qh5 also x-rays Pd5 through Ne5, intensifying interest in candidates clearing Ne5. The White Kg1 is vulnerable to back-rank mates, but is presently secured from check. Candidates (15.): Nxb5
15.Nxb5 Qxb5 [else, drop Bb5]
16.Nxf7 (threatening 17.Nd6++ 18.Nxb5 or 17.Nxd8+)
16…Rxf7 17.Rxe6+ Be7 [Kd7 18.Qxf7+ wins R+2P for N]
18.Rae1 (threatening 19.Rf6 winning Rf7 or 19.Rxe7+ winning Be7) 18…Kf8 [Qb4 19.a3 then 20.Rxe7+]
[else, the threats win Rf7 or Be7]
19.Qxh6+ Kg8 [Rg7 20.Rxe7]
20.Rxe7
White is up 2P, with threats on Kg8, Rf7, and Rd8. Black has no back-rank mate, and counter-attack with 20…Qxb7 (trying to recover material) is meaningless. |
|
| Jul-10-09 | | johnlspouge: I considered writing my times down, to comply with <al wazir>'s request on Wednesday, but I encountered a Heisenberg effect: the act of measurement perturbs my written analysis too much, and vice versa. Routine initial analysis of a position takes me less than 10 sec, e.g., but the act of writing and editing the first paragraph of the analysis below took closer to 10 minutes. By experience, I am also dubious that my subjective sense of time during analysis is worth much at all. On http://chess.emrald.net, where solutions are timed, the computer clock frequently disagrees violently with my own subjective clock. Bottom line: I would like to comply, <al>, but the exercise of timing myself is counterproductive to my purposes on CG. |
|
| Jul-10-09 | | TCS: <dzechiel> Well, will someone explain why black resigned when he did? I think this is a nice mid-week puzzle in its own right! I have the following as possible answers:
17...Be7 18.Rxe7 Kxe7 19.Re1+ Kd6 20.Qxf7 Qd7 21 Qf6+ Kc7 22.Re7 and the black Queen is dead. There are a few options instead of 19...Kd6 but in these cases the white queen starts eating rooks e.g. 19...Kf8 20.Qxh6+ Kg8 21.Kg5+ Kh8 22.Qxd8+ Kg7...
The overall problem is that Blacks pieces are unable support/protect one another. |
|
| Jul-10-09 | | percyblakeney: I had 17. ... Be7 18. Rael and never thought of the better 18. Rxe7+. |
|
| Jul-10-09 | | gofer: After a miss yesterday, I hope that I am better today... 15 Nxb5 Qxb5
16 Nxf7! (threatening Nd6+ winning the queen)
The main line is something like...
16 ... Rxf7 (Ke7 or Kd7 allows Nxd8, Rg6 allows Ne5 winning the exchange and probably two more pawns)
17 Rxe6+ Be7
18 Rxe7+ Kxe7
19 Re1+ Kd6 (not Kf6 which leads to mate)
20 Qxf7
Now black has lost 2 pawns, his king is wide open and both queen and rook are unprotected. White on the other hand has no obvious back rank mate issues to protect against, so more than likely has a winning position... Time to check... |
|
| Jul-10-09 | | SamAtoms1980: I got as far as 15 Nxb5 Qxb5 16 Nxf7 Rxf7 17 Rxe6+. At the table, that would have been enough. Bully. |
|
| Jul-10-09 | | butilikefur: 15. Nxf7 Rxf7 16. Nxd5 Qc6 (16...Qxd4 17. Rxe6+ Kd7 18. Qxf7+ Kc8 19. Qc7+ mate) 17. Rxe6+ Qxe6 18. Nc7+ Kd7 19. Nxe6 Kxe6 20. Re1+ wins the rook 20...Kf6 21. Qh4+ |
|
| Jul-10-09 | | butilikefur: whoa... I was wrong. |
|
| Jul-10-09 | | agb2002: Black has 2B+P for 2N but his king remains in the center. Therefore, remove the defenses with 15.Nxb5 Qxb5 16.Nxf7 A) 16... Rxf7 17.Rxe6+ Be7 (17... Rd7 18.Qxf7+) 18.Rxe7+ Kxe7 19.Re1+ A.1) 19... Kf8 20.Qxh6+
A.1.a) 20... Kg8 21.Qg5+
A.1.a.i) 21... Rg7 22.Qxd8+ Kf7 23.Re7+ Kg6 (23... Kf6 24.Rxb7+) 24.Qd6+ and 25.Rxg7 + -. A.1.a.ii) 21... Kf(h)8 22.Qxd8+ Kg7 23.Re8 (threatening 24.Rg8+ Kh6 25.Qg5#) + -. For example 23... Rc7 24.Rg8+ Kf7 25.Rf8+ Kg7 26.Qf6#, or 23... Rf5 24.Rg8+ Kf7 (24... Kh6 25.Qh4+ Rh5 26.Qf6#) 25.Rf8+ Kg6 (25... Ke6 26.Qc8+) 26.Qd6+ Kg5 27.Rg8+ Kh5 28.g4+. A.1.b) 20... Rg7 21.Qf6+
A.1.b.i) 21... Kg8 22.Qxd8+ transposes to A.1.a.i.
A.1.b.ii) 21... Rf7 22.Qxd8+ transposes to A.1.a.ii.
A.2) 19... Kd6 20.Qxf7 (threatens 21.Re6#)
A.2.a) 20... Qd7 21.Qf6+ Kc7 22.Re7 + -.
A.2.b) 20... Rd7 21.Qf6+ Kc7 22.Rc1+ Kb8 23.Qf8+ Rd8 24.Qxd8#. B) 16... Qxb2 17.Nxd8+ Kxd8 18.Qe5 (threatening Qxe6, Rac1 and Qb8+) Rg6 19.Rac1 + -. C) 16... Qb6 17.Nxd8+ Kxd8 18.Qe5 + -. |
|
| Jul-10-09 | | eblunt: This one seemed easier than some of the earlier ones in the week. The e6 pawn is an obvious target, and the deflecting the queen with ♘xb5 followed by ♘xf7 and ♖xe6+ gives an obvious strong attack for a very small amount of sacrifice ( ♘ for 2♙ ). I saw the weaker continuation of ♖ae1 double attack on the pinned ♗ but I'm happy enough with that. |
|
| Jul-10-09 | | goodevans: <Shyfe: ... 15. Nxf7 Rxf7 16. Nxb5 also wins, but less accurate as 16...Rdd7 gives a score of "only" +1.4 in Fritz> So I guess I count as "only" nearly right today! |
|
| Jul-10-09 | | gropek: Material is even, and in spot f7 knight and queen are atttacking it. So if i could take over the rook that is guarding f7... (that is my first thought) Then i saw that if i take the pawn with the horse, the rook will need to take it, and the rook is pinned to the king. Now if a take the pawn with my rook, the king will have to leave the defence, and i will win the rook, and the game in a few turns. The only problem is the queen, that is attacking the spot that i need to take with my rook. So, first, i need to take over the bishop with my horse, and after the queen takes it, i go into the plan: so, i think the best moves are: 15. Nxb5 Qxb5
16. Nxf7 Rxf7
17. Rxe6+ --- (now)
~~~~~
17 ... Be7
18. Rae8 (taking the bishop and after the rook).
~~~~~
17 ... Kd7
18. Qxf7+(win the rook) Kc8
19. Rc1+ now if
19... ♔b8
20. ♕c7+ ♔a8
21. ♕xd8# and {if
19... Bc5
20 dxc5 (win bishop)
Ok, that is it, time to check...
---
OH MY GOD! MY FIRST THOUGHT WAS EXACLY THE RIGHT ONE! I GOT IT IN A FEW SECONDS. :) I dont know if this one was easier, but im feeling pretty well, because i missed yesterday, but i did this one, that pretends to be harder... =D Time spent: less than 1 minute, just looking the screen, without seting up chessboards and stuff. |
|
| Jul-10-09 | | David2009: I missed 15 Nxb5 going instead for 15 Nxf7!? Rxf7 16 Nxd5 to be followed by Rxe6+. If the BQ captures the Re6 there follows Nc7+ and NxQe6. This seems to win but I have no way of checking my analysis for flaws (e.g. by Fritz which I don't have). <dzechiel: will someone explain why black resigned when he did?> Beats me! there is a lot of play in the position. |
|
| Jul-10-09 | | The Rocket: solved it!:P |
|
| Jul-10-09 | | randomsac: I guessed the solution correctly today. I saw that I could bust through by moving the black queen away from e6 and that I could barge through with Rxe6 (after removing the pawn with Nxf7). Then I figured that I could just plow through after Rae1. I felt that today's puzzle was rather simple. |
|
| Jul-10-09 | | CHESSTTCAMPS: Black is up a meaningless doubled pawn, but white has obvious pressure on the black king with the well-placed Qh5, Ne5, and Re1. This is an obvious setting for a demolition sacrifice to hit the base of the pawn chain (usual weak point, f7) and break up the central pawn shelter: 15.Nxf7! Rxf7
The double threat of Nxd8+ and Nd6+ makes acceptance mandatory. At this point I initially considered the weak followup Nxd5 and decided it didn't work. Instead, white should continue thematically - divert the queen from defense of e6. 16.Nxb5 Qxb5
17.Rxe6+ Be7
Again forced: after Kd7 18.Qxf7+ Kc8 19.Rc1+ Kb8 20.Qc7+ forces mate 18.Rxe7+!
The key move! Never give the defense a tempo to get organized if you can avoid it. 18... Kxe7
19.Re1+
A strong intuitive player may find this line by instinct, but it's really necessary to be able to foresee this position and its consequences from the problem position. A careful calculation shows that white wins in all variations: A) 19...Kf6 20.Qxh6+ Kf5 21.Re5+ Kg4 22.h3#
B) 19...Kd6 20.Qxf7 (threatening Re6# and Qe7+) Qd7 21.Qf6+ Kc7 22.Re7 wins C) 19...Kd7 20.Qxf7+ Kc8/c6 21.Rc1+ Kb8/b6/d6 22.Qc7+ wins D) 19...Kf8 20.Qxh6+ Kg8 21.Qg5+ Kf8 22.Qxd8+ Kg7 23.Re8! and black has no good defense to Rg8+ e.g. 23...Kg6 24.Rg8+ Kf5 (Rg7 25.Qd6+ Kf7 26.Rf8#) 25.Qg5+ Ke4 26.Qe3+ Kf5 27.Rg5+ Kf6 28.Qe5# D.1) 20...Rg7 21.Qf6+ Kg8 (Rf7 22.Qxd8+ transposes to the main D line) 22.Qxd8+ Kf7 23.Re7+ Kg6 (Kf6 24.Qf8+ or Rxb7+) 24.Qd6+ K-moves 25.Rxg7(+) wins Got the main idea here quickly but missed Wednesday's - go figure. |
|
| Jul-10-09 | | muralman: Well, ummmm that wasn't easy....... ;) |
|
| Jul-10-09 | | kevin86: First-divert the queen;second-sac the knight to remove the defender of the keystone pawn at e6;third-capture at that square and stand back as black's position crumbles. |
|
 |
|
|
< Earlier Kibitzing · PAGE 2 OF 3 ·
Later Kibitzing> |
Kibitzing
sac: 16.Nxf7
