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Ian Rogers vs Trevor Tao
ch-AUS (2004), Adelaide AUS, rd 5
French Defense: Winawer. Petrosian Variation (C16)  ·  1-0

ANALYSIS [x]

FEN COPIED

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Kibitzer's Corner
< Earlier Kibitzing  · PAGE 2 OF 2 ·  Later Kibitzing>
Sep-26-09  TheStormofWar: millsms: Real stupid question because I am new to this. Why doesn't any of these games go all the way to checkmate?

Mainly because the player that resigns either runs out of time, has a position that is untenable (checkmate cannot be avoided usually), or material loss that has happened (or will) that is not properly compensated for (usually with a good position, gained time or tempo, etc).

Sep-26-09  patzer2: <millsms> Many games in our database do end in checkmate. Many others don't because one player has sufficient advantage to force mate, the opponent clearly regcognizes this fact, and as permitted by the rules of the game (and encouraged by the unwritten rules of etiquette) resigns.
Sep-26-09
Premium Chessgames Member
  johnlspouge: < <PinnedPiece> wrote: Boy, I didn't consider 19.Nxd5 because I thought 19...Qxd5 led to [snip] after 20.Qxd5 pxd5 21.Bxc6 Bb7 [snip] What am I missing? This doesn't look convincing for white. >

Toga evaluates the position at about 2 P. After

22.Bxb7+ Rxb7 23.a3

White has consolidated his extra P, and he has a manifestly better developed position.

Kotov's Rule is to stop calculation when a clear P has been won. The Rule is invaluable for moving on instead of agonizing over exactly the type of position you display (and it is particularly valuable in analyzing sham sacrifices that win a P.) Except as an exercise for improve your board vision, the position you display should be considered won at a clear P up: it not worth the effort of calculation.

Sep-26-09  patzer2: Ian Rogers sham sacrifice 19. Nxd5!! initiates a combination using the clearance, deflection and pinning themes to win decisive material.

Black could have put up a bit more resistance with 19...Qxd5. However, <RV>'s post of Ryba 3 analysis seems to indicate White may still have enough advantage to win the endgame.

Sep-26-09  remolino: Millsms - At Master level (even at below Master but Experienced level of play), players can tell when a position is lost, either because mate can be calculated with precision several moves ahead, or simply because the position is lost strategically. That is, you really do not expect your opponent to make a huge mistake.

So players resign to show respect, but also not to have to sit at the board while your opponent shows you how to win an obviously won position.

But there is a saying that says that no one ever won a game by resigning, so a player always has the undisputed right to continue playing no matter how bad his/her position may be, and it is not acceptable to pressure your opponent to resign in any position.

Sep-26-09  PinnedPiece: < Except as an exercise for improve your board vision, the position you display should be considered won at a clear P up: it not worth the effort of calculation.>

Yes, I suppose this is all true when there are no more advantageous trades to make, as you indicate.

Sep-26-09
Premium Chessgames Member
  Jimfromprovidence: I diverted from the text beginning with 20...Qb7, followed by 21 exf7 Bxg5 22 fxg8Q Rhxg8.


click for larger view

I kind of like 23 Qxd5, (seeing Bxc6) here, but it looks pretty difficult to find a clear way forward.

Sep-26-09  310metaltrader: resignation is simply the way to avoid a loss of time that cannot be recovered. why do basketball games go on when the winning team is 20 points ahead with a minute to go?
Sep-26-09  BOSTER: White has a good development, more space . Black behind in development, bishop a6 unprotected, Nc6 is pinned, not enough protection. White has to use time untill N g8 and Rh8 out of game. First idea to move Knight to e5 to put more pressure on pinned Nc6, but now on e5 we have white pawn. So we have to move it. This tactic is called clearance sacr. Let's begin 19.Nxd5 exd5
20.e6 fxe6
21. Ne5 Qc7
22. Nxc6 Re8
23.Rxe6 Bc8
24.Rxe7 Nxe7
25. Nxe7 Rxe7
26.Bxe7 Qxe7
27. Bc6+ Bb7
28.Qxd5 Bxc6
29.Qxc6 and white has the winning position.
Sep-26-09  goodevans: Got the first three moves pretty quickly. Methinks it's quite easy as Saturday puzzles go.
Sep-26-09  millsms: Thank you all for your responses. I hope to begin to understand this game in full. Possibly the most complex and mentally satisfying game I have played yet.
Sep-26-09  muralman: Too many moves. I got the first three, then went awry. Actually, the ending wasn't all that gratifying. My expectations are obviously too high.
Sep-26-09  LIFE Master AJ: After considering many different alternatives ... I nailed this one! (Nxd5 and e6) The main idea is to clear e5 for White's Knight.

Below are some really quick thoughs and analysis:

18.Ba4 Rb8;
Black's last move was close to being forced here. (Black had to stop White's threat of b4-b5, for beginners.)


click for larger view

We have now reached the position for the CG "Problem of The Day." (daily puzzle)

19.Nxd5!!,
White has a few promising ideas here, but this is best.

[ I also looked at 19.b5, which is also good for White. For example: 19.b5 Bxb5; 20.Bxb5 Rxb5; 21.c4 Rb4; 22.cxd5 Bxg5; 23.Nd3±. ]

19...exd5; (Forced. White has the threat of Nb6+; winning the BQ on d7.)

20.e6 fxe6!?; ('?!')
This may not be best.

[I had originally calculated: 20...Qc7; 21.exf7 Bxg5; 22.Nxg5 Nge7; 23.Ne6 Qd7; 24.Nxc5, " " etc.]

The rest does not really require a lot of comment.
21.Ne5 Qc8; 22.Nxc6 Rb7; 23.b5 Bxg5; 24.bxa6 Rb6; 25.hxg5 Rxc6; 26.Bxc6+ Qxc6; 27.Qe2, 1-0

Sep-26-09
Premium Chessgames Member
  agb2002: Material is even. Black threatens to win a pawn with ... cxb4. White can try to take advantage of the pinned knight with 19.Nxd5:

A) 19... exd5 20.e6

A.1) 20... fxe6 21.Ne5

A.1.a) 21... Nxe5 22.Bxd7 Nxd7 23.Bxe7 Nxe7 24.Rxe6 + -, with multiple threats: 25.Rxe7, 25.Rxa6, 25.Qxd5.

A.1.b) 21... Qd6 22.Bxc6+ Bb7 23.Bxb7+ Rxb7 24.Nf7 + -, winning the exchange at least.

A.1.c) 21... Qc7 22.Bxc6+ Bb7 23.Bxb7+ Rxb7 24.Nxg6 Rh7 (24... Bxg5 25.Nxh8 Bxh4 26.Ng6) 25.Nxe7 (25.Bf4 Bd6) Nxe7 26.Rxe6 + -, [2P].

A.1.d) 21... Qc8 22.Bxc6+ Bb7 23.Bxb7+ (23.Bd7 is probably enough to get advantage but looks much more complex) Rxb7 24.Nxg6 Rh7 25.Bxe7 Nxe7 26.Nf4 cxb4 27.cxb4 Rxb4 28.Nxe6 with the better position and a pawn ahead.

A.2) 20... Qc7 21.Bxc6+ (21.Qxd5 Bb7 is unclear) Qxc6 22.exf7

A.2.a) 22... Nf6 23.Rxe7, threatening 24.Bxf6 Qxf6 25.Qxd5+ and 24.Ne5.

A.2.b) 22... Bxg5 23.Ne5 Qb7 24.fxg8=Q Rhxg8 25.hxg5 cxb4 26.cxb4 Qxb4 27.Qxd5+ Bb7 and it's not clear that the extra pawn will be enough to guarantee the victory.

B) 19... Qxd5 20.Qxd5 exd5 21.Bxc6+ Bb7 22.Bxb7+ Rxb7 23.Bxe7 Nxe7 24.a3 with the better position and a pawn ahead.

C) 19... cxb4 20.Nxe7 Nxe7 21.Bxe7 + - [B].

Sep-26-09
Premium Chessgames Member
  fm avari viraf: It seems to me that White is having a dominant position & can invade Black's vulnerable territory with the most promising 19.Nxd5 the idea is to simply push the e-pawn after Black captures with 19...exd5 & now 20.e6 fxe6 [of cousre Black can move the Queen to 20...Qc7 21.exf7 & now either 21...Nh6 then 22.Bxh6 or 21...Bxg5 22.fxg8=Q looks good for White ] 21.Ne5 Qc8 22.Nxc6 Rb7 23.b5 & Black is in the whirlpool of agony.
Sep-26-09  TheBish: I Rogers vs T Tao, 2004

White to play (19.?) "Very Difficult"

Material is even. I only had one candidate move, it was just a matter of making it work!

19. Nxd5! threatens 20. Nb6+ (winning the queen) as well as 20. Bxc6+ Qxc6 21. Nxe7 (winning a piece), so clearly the knight must be accepted.

19...exd5

19...Qxd5 20. Qxd5 exd5 21. Bxc6+ Bb7 22. Bxb7+ Rxb7 23. a3 wins a pawn for White

20. e6 fxe6

or 20...Qd6 21. bxc5 Qxc5 22. Bxc6+ Qxc6 23. exf7 Bxg5 24. hxg5! and White will regain the piece with a pawn up

21. Ne5 (the point of the sacrifice) and now:

A) 21...Nxe5 22. Bxd7 Nxd7 (or 22...Bxg5 23. Rxe5) 23. Rxe6 and the rook fork will gain White a piece, leaving Black with only two pieces for the queen.

B) 21...Qc7 (not 21...Qd6 22. Bxc6+ Bb7 23. Bxb7+ Rxb7 24. Nf7) 22. Nxc6 and now:

B1) 22...Rb6 23. Rxe6 Bxg5 (or 23...Rh7 24. Rxg6) 24. Qxd5! and White will regain the piece at least two pawns up, since 24...Bxh4 allows 25. Re8+ Bc8 (or 25...Kb7 26. Na5#) 26. Ne7+ Kb8 27. Rxc8+ Qxc8 28. Nxc8 Kxc8 29. Qa8+ Kc7 (or 29...Rb8 30. Qc6+ Kd8 31. Qd7#) 30. Qxa7+ wins the rook, leaving White ahead a queen for a knight.

C) 21...Bxg5 22. Nxb8 Kxb8 (22...Bxh4 23. Nxa6 is even better for White) 23. hxg5 wins an exchange for White.

Time to see how this went down.

Sep-26-09  gofer: I looked at b5 and Bxe7 for sometime and during these I eventually realised that Nxd5 was quite nice, so then I back tracked and instead started with Nxd5 which wins easily.

OTB I dont think I would have seen this...

:-(

19 Nxd5 (threatening 20 Nb6+ winning the queen)

The refusals...

19 ... Qd8 20 Bxc6+ winning
19 ... Qc8 20 Bxc6+ Qxc6 21 Nxe7 winning
19 ... Rb7 20 Nxe7 Ngxe7 21 Bxe7 Qxe7 22 Bxc6 winning

19 ... Rd8 20 Nxe7 Ngxe7 (Qxd1 21 Bxc6+) 21 Qxd7 Rxd7 22 Bxc6+ winning

The acceptance...

19 ... exd5
20 e6

If black doesn't play 20 ... fxe6 then the queen has to move and Qb7, Qc8, Qc7 and Qe8 are the only ways to protect against Nxc6+, but all of them lose to 21 exf7 as Rxe7 is threatened and fxg8=Q and so black is going to lose a piece.

20 ... fxe6
21 Ne5!

Now we come to the point of the original sacrifice, the Knight on c6 can't move because the queen will be taken, but if the queen moves then Bxc6+ or Nxc6 is going to be played!

The refusals...

21 ... Qd6 22 Nf7 winning
21 ... Qd8 22 Nxc6 winning
21 ... Qc7 (or Qc8) 22 Bxc6+ Bb7 23 Bxb7+ Qxb7 24 Nxg6 Rh7 25 Rxe6 Bxg5 26 hxg5 and white is two pawns up with the black knight trapped as Ne7 allows Rxe7 Rxe7 Nxe7 Qxe7 Qxd5+ winning another pawn and the cxb4 is followed by Rb1 winning

The acceptance...

21 ... Nxe5
22 Bxd7 Nxd7
23 Rxe6 ...

23 ... Bxg5 24 Rxa6 Bd8 25 Qxd5+ Rb7 26 bxc5 Nf6 27 Qc6 Ne6 28 Qa4 with c6 to follow which is game over...

23 ... Bb7 24 Bxe7 Nxe7 25 Rxe7 Rhd8 26 bxc5 Nxc5 with Rb1 and then a4 etc to follow which is game over...

Time to check...

Sep-26-09  zb2cr: I'm feeling distinctly put out. Looks as though mostly everyone but me saw the correct move 19. Nxd5--while all I could see was 19. Bxe7, Ngxe7; 20. bxc5 to win a Pawn.

Bad board vision! Bad board vision!

Sep-26-09  patzer2: <RV> I've read three different suggestions for 20...Qc7. I like the recommendations of both <LIFE Master AJ> and <fm avari viraf>. However, I'm wondering, What does Rybka 3 suggest?
Sep-26-09  WhiteRook48: I tried something stupid like 19 Nd4
Sep-26-09  AxelBoldt: I saw 19.Nxd5, but I was afraid of 19...Bxg5 20.hxg5 exd5 21.e6 Qc7 22.exf7 Ne7. Or should White take with the knight on g5?
Sep-26-09  nigelcooper: One other defence B could try is, after 1 Nxd5 exd5 2 e6, 2 ... Qb7, after which a likely continuation is 3 exf7 Bxg5, 4 fxg8=Q Rbxg8, 5 hxg5 Bc4, 6bxc5 h4, 7 Re6 Nd8, 8 Ne5 h3, 9 Rb1 hxg2, 10 Rxb7 Rh1+, 11 Kxg2 Rxd1, 12 Rxa7+ Kxa7, 13 Re7+ Ka6, 14 Bxd1 and W still comes out with a clear win. A little more exciting than some of the other variations, for both sides.
Sep-26-09  RandomVisitor: After the proposed improvement 20...Qc7:

1: Ian Rogers - Trevor Tao, ch-AUS Adelaide AUS 2004


click for larger view

Analysis by Rybka 3 : <17-ply>

1. (3.01): 21.exf7 Bxg5 22.Nxg5 cxb4 23.Qxd5 Bb7 24.Ne6 Qxf7 25.Bxc6 Nf6 26.Bxb7+ Rxb7 27.Qc6 Ng4 28.f3 Qd7 29.Qxd7 Rxd7 30.fxg4 bxc3 31.Nf4 hxg4 32.Rac1 Rc8 33.Kf2 Rd6 34.Kg3

2. (2.70): 21.Qxd5 f6 22.Bxc6+ Bb7 23.Bxb7+ Qxb7 24.Qxb7+ Rxb7 25.Bd2 Nh6 26.Bxh6 Rxh6 27.a3 Rh8 28.Rad1 Kb8 29.Nd2 cxb4 30.cxb4 Rc7 31.Nb3 Kc8 32.Rd3 Rd8 33.Red1

3. (2.09): 21.Bxc6+ Qxc6 22.exf7 Bxg5 23.hxg5 Qb7 24.fxg8Q Rhxg8 25.bxc5 Rbc8 26.Rb1 Qc6 27.Qc2 h4 28.Nxh4 Qxc5 29.Re6 Rc6

Sep-27-09  patzer2: Thanks <RV>. Looks like all three suggestions had winning potential. Rybka's suggestion seems to win, but finding it OTB might be difficult.
Sep-28-09  mworld: <LIFE Master AJ: After considering many different alternatives ... I nailed this one! (Nxd5 and e6) The main idea is to clear e5 for White's Knight.

19...exd5; (Forced. White has the threat of Nb6+; winning the BQ on d7.)>

Hello AJ, I really enjoy your posts and try to play through your analysis to learn, but in this one I got confused; why would you call the above forced without examining 19...Qxd5 which avoids the threat you list as being the reason for the move being forced?

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