26 October 2017

Trends in chess openings - personal observations


The above chart (based on August 2017 TWIC data) was recently highlighted in a ChessBase news article.  As usual, the best way to view any statistics is with a critical eye.  With that in mind, here are some observations related to my personal repertoire, which I know best, and some other opening trends that are highlighted.

At first I was surprised at the high popularity of the Caro-Kann (#4), my primary defense to 1. e4, but after you start adding up the various Sicilian variations, it makes more sense and does not in fact represent a big surge for the Caro-Kann.  The main point is that the Caro-Kann is reliably popular and a solid choice at the professional level (more on that point below), to the point of beating out the most popular variation (Najdorf) of the Sicilian.

Likewise with the Slav (#7), my primary defense to 1. d4, but that actually seems to be more logical as a separate category in the queen pawn opening complex, with the main 1...Nf6 choices ahead of it.  It's interesting to note that it does beat out the more historically popular Queen's Gambit Declined, but only (I expect) if you include the Semi-Slav complex of openings, which I don't have in my repertoire.

On the White side, it was nice to see the English well represented, with various main trunks taking up 4 of the top 20 spaces.  This makes sense, as it's a great must-win opening (said only partly jokingly).  It's worth noting that the reply 1...e6 is on the list, as in opening manuals it's often treated as a sideline (if at all).  While there are a lot of transpositional possibilities, it's something that every English player should look at.

A couple of general observations on the list:
  • The absence of the Ruy Lopez / Spanish Game is not completely shocking, if you've been paying attention to the top-level games over the last couple of years, but is still very interesting as a novel historical development.  Basically the top White players seem to have switched to the Giuoco Piano (#18) as holding better prospects for advantage.  Seeing the Caro-Kann at #4 and the Ruy Lopez nowhere on the list is still a bit weird, at least for those of us who have been playing for more than a decade.  The "Spanish Torture" seems to have lost its edge.
  • The #1 place for the Reti in my opinion is a reflection of the trend at the top, especially with players like Carlsen and Kramnik, to adopt a meta-strategy of "just playing chess" and seeking to win by relying on a deeper understanding of their game, rather than trying to fight it out in a theoretical duel.  This is a common idea at any level, actually, as the strategy seeks to take away the advantage of "free good moves" that a lower-rated player is offered by going into a well-prepared and analyzed line for 15-20 moves.  The caveat, of course, is that you actually do have to have superior knowledge of the resulting position-types, even if things like exact move orders are not always crucial, or there is a lack of forcing moves.
  • I have to admit I was surprised by the continuing popularity of the Modern Defence (#20), as I thought its peak time was past.  On the other hand it's a flexible choice, can be played in response to pretty much any White first move, and has the advantage noted above of being less forcing and more favorable to someone who knows the resulting positions and their requirements well.
  • In general, I tend to look at the "top openings" lists as indications of what master-level players consider to be completely solid openings that will yield the best chance for an advantage and/or counter-play.  Openings which are viewed as now being too drawish (the Ruy Lopez now, along with the Petroff) drop off in use as a result, but this lack of professional popularity should by no means influence amateur opening choice, when the openings in question are actually too solid rather than questionable.

27 September 2017

Annotated Game #180: At least it wasn't a draw (?)

This last-round tournament game is a thankfully rare example of how poor attitude can lead directly to an otherwise undeserved loss.  I get a small advantage out of the English Opening versus a King's Indian Defense setup, getting two open files on the queenside that my pieces should have done more with.  Instead, I miss a great tactic on the long diagonal on moves 19 and 20, then play too passively in response to an unexpected central pawn advance.  This leads almost immediately to unwarranted panic on my part, due to lazy (or nonexistent) calcuation, and a rapid implosion.  The turnaround is sharp and totally psychological.

So why did that happen?  You may have noticed that all of the previous games in this tournament ended in draws for me - some rightly so, others due to my squandering or simply not pursuing an existing advantage.  I was determined not to have a draw in the last round, which while understandable was simply the wrong mental attitude to adopt going into the game.  One cannot just impose one's will on the chessboard.  Your opponent always gets a vote and focusing on your desired outcome (a win) simply wastes mental energy and distracts you from what the goal should be, which is to play well and thoughtfully in every position.  Point taken.

[Event "?"] [Site "?"] [Date "????.??.??"] [Round "?"] [White "ChessAdmin"] [Black "Class C"] [Result "0-1"] [ECO "A26"] [Annotator "ChessAdmin/Komodo 10"] [PlyCount "70"] [EventType "simul"] [EventRounds "5"] 1. c4 Nf6 2. Nc3 g6 3. g3 Bg7 4. Bg2 O-O 5. Nf3 d6 6. O-O e5 7. d3 {the standard KID setup against the English.} Nc6 8. Rb1 a5 9. a3 Ne7 10. b4 axb4 11. axb4 Ne8 {a funny-looking retreat, but it does allow the f-pawn to advance afterwards.} 12. Bg5 {this doesn't do a whole lot for me, as the bishop doesn't have much of a future on g5.} (12. b5 $5 c6 13. Bd2 $14) 12... c6 13. b5 f6 {it's not a bad move to kick the bishop, but it does neglect development for a tempo and locks his Bg7 in further.} (13... h6 {seems more logical.}) 14. Bd2 Be6 15. bxc6 (15. Na4 {is the idea Komodo prefers, eyeing the b6 square.}) 15... bxc6 16. Qc2 {after the initial exchanges and development now complete, the position is looking a bit drawish. I still have a slight pull in my favor, with the open queenside more easily accessible to my pieces, but it's not much of an advantage.} Qd7 {this really invites the Na4 idea, but it's also good to double rooks on the b-file.} 17. Rb6 (17. Rb4) 17... Nc8 18. Rb4 {this could have been a sly, trappy idea had I spotted the weakness in Black's next move, which I even anticipated.} c5 $2 19. Rb3 {this should be good enough for an advantage, but there's a tactical refutation of Black's last pawn push, which opens up the long diagonal.} (19. Nxe5 $1 fxe5 20. Rb7 {it's this follow-up move which is particularly difficult to see, if you're human.} Qd8 21. Rxg7+ Nxg7 22. Bxa8 $18 {White is a pawn up now, but more importantly will now easily dominate the board with his pieces.}) 19... Bh3 20. Rfb1 (20. Nxe5 $1 { is now a great idea that is much simpler to calculate.} fxe5 21. Bxa8 Bxf1 22. Kxf1 $18) 20... Bxg2 {unfortunately, after this there are no longer any tactics on the long diagonal for me.} 21. Kxg2 Ra7 22. Qb2 $16 {although I've passed up some opportunities, it's still looking good for me on the queenside. The Nc8 is poorly placed and I dominate the b-file. Now I plan to eliminate Black's Ra7 and work towards controlling both open files.} Rf7 23. Ra1 Rxa1 24. Qxa1 Qa7 25. Ra3 (25. Qb1 {keeping control of the b-file looks better, with the threat of invading the rook on b8.}) 25... Qd7 26. Nb5 {this is not a bad move, but here I start "losing the thread" of the game, as they say. Black's next move comes as an unpleasant surprise and I react poorly.} d5 {this is really a false threat, in the sense that my position is still advantageous, but it help Black take the initiative, since I don't find the only reply that keeps the advantage.} 27. Qc1 $6 $11 {I had been worried about the threat of losing the Bd2 to a discovered attack on the d-file.} (27. Ra8 $16 {correctly ignores Black's central pawns and pressures the 8th rank, with Qa6 being the main threat.} e4 28. Ne1 {and now if} dxc4 $2 29. Qa6 $1 $18) (27. Be3 $14 { would have been a safe choice that preserved some of my queenside pressure.}) 27... Nb6 {and now I just unreasonably panic and fall apart.} 28. Bh6 $2 { pretty much any reasonable move here keeps the balance. Instead...} Bxh6 29. Qxh6 dxc4 {now Black is a pawn up for nothing and I decide to try unsuccessfully for a swindle. It's pretty ugly.} 30. Ra7 Qxb5 31. Rxf7 Kxf7 32. Qxh7+ Ng7 33. Nh4 Qc6+ 34. f3 f5 35. g4 fxg4 0-1

21 September 2017

Annotated Game #179: An IQP lesson

This game is almost completely characterized by my strategic struggle against Black's isolated queen pawn (IQP), a normal result of the Tarrasch Defense.  The notes speak for themselves, with the key (wrong) choice made by me on move 24, thanks to a deflection tactic that makes my chosen sequence of moves lead to a very drawish position, rather than maintaining my positional advantage.  I could also have done a bit more with my knights, but that was the key strategic error and another (IQP) lesson learned.

[Event "?"] [Site "?"] [Date "????.??.??"] [Round "?"] [White "ChessAdmin"] [Black "Class C"] [Result "0-1"] [ECO "A13"] [Annotator "ChessAdmin/Komodo 8"] [PlyCount "56"] [EventDate "2016.10.10"] [EventType "schev"] [EventRounds "5"] {[%mdl 8192] A13: English Opening: 1...e6} 1. c4 e6 2. Nf3 d5 3. e3 Nf6 4. b3 Be7 {now in a standard QGD type setup for Black.} 5. Bb2 Nbd7 6. Be2 b6 7. O-O Bb7 8. Nc3 (8. d3 {is an option, with the idea of Nbd2.}) (8. cxd5 $5 { immediately is more common than the text move.}) 8... O-O 9. cxd5 {this seemed the logical follow-up. I've previously had bad experiences with Black building a strong pawn center and this takes care of that problem.} Nxd5 (9... exd5 10. Rc1 Re8 11. Qc2 Bf8 12. Rfd1 c6 13. d4 Bd6 14. Bd3 Qe7 15. Ne2 g6 16. Ng3 Ng4 17. Re1 f5 18. Bxf5 gxf5 19. Nxf5 Qf8 20. e4 Bf4 21. e5 Re6 22. Rcd1 Kh8 23. g3 Qg8 24. Kh1 {Gunina,V (2529)-Kriebel,T (2461) Novy Bor 2015 1/2-1/2 (157)}) 10. Rc1 (10. Nxd5 {is more common. The Nc3 isn't a great piece and it's better to exchange it, also opening up the long diagonal for the Bb2 (and the c-file for a rook).} Bxd5 11. Qc2 c5 12. Rad1 Rc8 13. Qb1 Qc7 14. d4 Qb7 15. Rc1 cxd4 16. Bxd4 Bf6 17. Qb2 Bxd4 18. Qxd4 Nf6 19. h3 h6 20. Qa4 a5 21. Qd4 Rc7 22. Qe5 Rfc8 23. Ba6 {1-0 (23) Alekseev,E (2679)-Rusanov,M (2440) St Petersburg 2014}) 10... Bf6 11. d4 {here I decided the benefits of the pawn advance outweighed shutting off the Bb2. First of all, Black's Bf6 is also shut out, and I also get a strong central pawn that influences e5 and c5. The a3-f8 diagonal also looks like a good one for my bishop.} Rc8 $146 {a slow move and one that allows the following sequence, giving me a measurable edge.} (11... Nxc3 12. Bxc3 c5 $11) 12. Nxd5 $14 Bxd5 (12... exd5 13. Ne5 Nxe5 14. dxe5 Be7 15. Bg4 Ra8 16. Qc2 c6 17. f4 $14) 13. Ba6 {this is the problem with the earlier rook move, Black loses a tempo and his queenside is looking awkward.} Rb8 14. Bd3 { I had been worried about a possible future ...b5, blocking the bishop in. Another square might have been better, though.} (14. Bb5) (14. Qe2 {is another option the engine likes, controlling the diagonal (and b5) while connecting the rooks and protecting the Bb2, which is otherwise loose.}) 14... c5 { the logical reaction by Black, taking advantage of the unprotected Bb2 to rule out capture on c5.} 15. Ne5 {a somewhat risky and aggressive decision that was not the best. I didn't mind the exchange on e5, and it is evaluated by the engine as equal.} (15. Qe2 cxd4 16. Nxd4 Rc8 $14) 15... Bxe5 $6 {a case where the standard rule of not exchanging bishops for knights applies.} (15... cxd4 $5 16. exd4 Nxe5 17. dxe5 Be7 $11) (15... Nxe5 16. dxe5 Be7 $11) 16. dxe5 $14 { White has the pair of bishops, but also the Nd7 has no useful squares at the moment.} Qg5 {this surprised me, but I was able to find an effective countermove.} 17. e4 {now I have the initiative.} Bc6 18. f4 {the queen's location becomes a problem for Black.} Qh4 19. Rc2 (19. Rc3 $5 {is probably a better version of the idea of transferring the rook to the kingside (after Bc2) and one that I considered for a while. In the end I rejected a plan of a piece attack on the kingside for one based on a pawn advance.} Qe7) 19... Rbd8 20. g3 (20. Qe2 $16 {getting off the d-file and overprotecting e4 was an excellent idea.}) 20... Qh3 $6 {this over-optimistic move justified my play to this point.} (20... Qe7) 21. Rd2 $16 {screening the Qd1 and protecting the Bd3 again.} f6 $2 {causes even greater problems, in part because the Qh3 now has no safe retreat. It also weakens e6, which I take advantage of (but not well enough).} (21... Nb8 $16 {looks sad, but otherwise Black has serious problems.} ) 22. f5 {I thought for a while here and felt good about the move, which presses the attack, but is rather complicated given the various captures on e5, f5 and e6.} (22. Be2 {is found by the engine the threat being to play Bg4 with a fork on e6.} f5 (22... h5 23. exf6 Bxe4 24. Rf2 gxf6 25. Bxh5 $18) 23. Bc4 Rfe8 24. Rd6 Bxe4 25. Rf2 Qh6 26. Rfd2 $18) 22... Kh8 $2 (22... Qh6 23. Bb1 Qe3+ 24. Rff2 $18) 23. Rf4 $1 {this should be sufficient to win. The threat of course is Rh4, trapping the queen.} Qh6 24. Rh4 $4 {here I moved too quickly and had a major thinking process foul. I had assumed that the queen was trapped, but of course it now has e3 to go to, with devastating effect. This was a case of the actual piece placement (Rf4) interfering with my mental visualization of the future board (Rh4, Qh6), where the diagonal is no longer blocked. Naturally if I had followed my thinking process, I could have corrected for this.} (24. fxe6 $1 {and wins.} fxe5 25. Rxf8+ Nxf8 26. e7 $18 { I had in fact looked at this variation, but was tired and having trouble visualizing. And then it occurred to me (mistakenly) that I could just play Rh4.}) 24... Qe3+ $19 {after this it is game over, although I fight on for a few moves in the vain hope for a swindle.} 25. Kf1 Nxe5 26. Qh5 Qf3+ 27. Ke1 Qxh5 28. Rxh5 Nxd3+ 0-1

02 September 2017

Annotated Game #178: Patience is a virtue...which I lack

Analysis of this next tournament game, along with the previous ones, helps highlight one recurring flaw in my play: lack of patience.  This is a common fault in Class players, often reflected in the idea that each single move has to "do something" big.  Here, as in Annotated Game #176, when there is no obvious immediate breakthrough, I get frustrated and acquiesce to a draw.  Fixing this conceptual flaw in my play should bring better results over time.

The game itself contains some interesting ideas (not just psychological ones), including alternatives for Black on move 9 and move 12.  As part of the analysis process, it's very useful to see how modern engines (Komodo 10 in this case) help evaluate plans, not just individual moves; for example, it consistently highlighted the value of the b8-h2 diagonal and building up pressure on it through the variations on moves 12 and 15.  I also like the idea of the knight retreat on move 19, getting out of the way of the pawns and playing a more maneuvering type of game.  Finally, it was worth looking at the different options towards the end of the game, for both dynamic and maneuvering play, to continue working my positional advantage.

[Event "?"] [Site "?"] [Date "????.??.??"] [Round "4"] [White "Class C"] [Black "ChessAdmin"] [Result "1/2-1/2"] [ECO "D00"] [Annotator "ChessAdmin/Komodo 10"] [PlyCount "47"] [EventType "simul"] [EventRounds "5"] 1. d4 d5 2. e3 {usually an indicator that White is heading for a Stonewall formation.} Nf6 3. Bd3 c5 4. c3 Nc6 5. f4 Bg4 {getting the bishop to an active square before playing ...e6} 6. Nf3 e6 7. Nbd2 Be7 8. O-O O-O 9. Qe1 cxd4 { Normally it's a good idea to exchange c-pawn for d-pawn, and it isn't bad here. But there may be a more effective path forward for Black.} (9... Bf5 {is a more sophisticated positional idea, which is both the database and engine favorite. After} 10. Bxf5 exf5 {Black has a lock on e4 and White's e3 pawn will be weak on the half-open file.}) 10. exd4 Rc8 11. Ne5 Bf5 {I'll give myself credit for recognizing this idea, even if a bit later than optimal.} 12. Qe2 a6 {this was perhaps a waste of time. My idea was to play follow up with .. .b5 and prevent White from advancing the c-pawn to exchange off my d5 pawn. However, this is not a real threat as long as the Nc6 is there (due to the d4 pawn then being unprotected). If White exchanges on c6, then a subsequent pawn swap on d5 would just leave d4 isolated and weak.} (12... Qc7 $5 {would develop the queen and connect the rooks. It also starts to build pressure up on the b8-h2 diagonal.}) 13. Qf3 b5 {sticking with the original idea.} 14. a3 $6 {done to prevent b5-b4, but this is too weakening.} Na5 $15 {now having a pawn on b5 is actually helpful, thanks to my opponent making holes on the queenside.} 15. Re1 Re8 {not really necessary. Komodo still favors the plan of building pressure on the b8-h2 diagonal with ...Bd6 and ...Qc7.} 16. g4 Bxd3 17. Nxd3 Nc4 18. Nxc4 bxc4 {now I enjoy a significant space advantage in the center and on the queenside.} 19. Nf2 g6 (19... Nd7 $5 {would activate the Be7 and give White fewer kingside targets for the pawns.}) 20. Qh3 (20. f5 exf5 21. gxf5 Rb8 $15) 20... Bf8 {rather too cautious.} (20... Rb8 {with the idea of pressuring the b-pawn and forcing White to tie down a piece to its protection.} ) 21. Bd2 $6 {White will just have to move this back next move.} Rb8 $17 22. Bc1 Qb6 {here either more patience was called for in a largely closed position, or some more dynamic play.} (22... h5 $5 {is the dynamic option.} 23. gxh5 Nxh5 $15) (22... Re7 {is a more slow maneuvering approach, clearing the e8 square for the knight to go to d6 and perhaps to double rooks on the b-file.}) 23. Qg3 Bd6 24. Qf3 {at this point I saw no obvious breakthroughs for Black, so took the draw. Basically a lack of energy and patience was the reason, along with not really understanding the needs of the position. These include the importance of the b8-h2 diagonal and activating the bishop, the possible ...h5 advance, better and earlier development of the queen and rooks, etc.} 1/2-1/2

26 August 2017

Annotated Game #177: How could I not win this?

While it's always disappointing to lose a game, there's another - sometimes just as poignant - feeling of disappointment at not winning a game.  This next tournament game falls into that category.  I build up excellent attacking prospects on the kingside, with open lines and an overwhelming local superiority of pieces (4-0), but at the crucial point I failed to actually execute an attack.  My opponent started to do a good job of defending while making threats and turned the game around as a result; what happens after move 27 is an excellent illustration of the importance of the initiative, both on the board and psychologically.  I almost had the full disappointment of losing the game, as things went rapidly downhill, but after an error by my opponent I managed to calculate the drawing sequence and wrapped the game up.

Analyzing this game was helpful in highlighting certain clusters of turning points and strategic choices, for example around moves 17-19 and again on moves 27-31.  Hopefully I can make better future decisions as a result.

[Event "?"] [Site "?"] [Date "????.??.??"] [Round "?"] [White "ChessAdmin"] [Black "Class C"] [Result "1/2-1/2"] [ECO "A28"] [Annotator "ChessAdmin/Komodo 10"] [PlyCount "81"] [EventType "simul"] [EventRounds "5"] 1. c4 e5 2. Nc3 Nf6 3. Nf3 Nc6 4. e3 d5 5. cxd5 Nxd5 6. Bb5 Nxc3 7. bxc3 Bd7 8. d4 Bd6 9. O-O O-O 10. Be2 Re8 11. Qc2 e4 12. Nd2 {now e4 becomes an easy target to focus on, although the position is still equal.} Re6 $2 13. f4 { here I believed my opponent a little too much, when he failed to defend e4, although the text move is also good for White.} (13. Nxe4 {I correctly saw there was a threat for Black involving ...Qh4, which made me avoid this line. However the engine shows that this is unnecessary, since Black's attack just looks scary rather than being effective.} Qh4 (13... Bxh2+ 14. Kxh2 Qh4+ 15. Kg1 Qxe4 16. Qxe4 Rxe4 17. f3 Ree8 18. Kf2 $16) 14. f4 Rh6 15. h3 Rg6 16. Bf3 Bxh3 17. Nxd6 cxd6 $16 {and White is fine.}) 13... exf3 14. Nxf3 $16 {here Komodo considers White to be about the equivalent of a pawn ahead. The central pawns are quite powerful and I have some nice open lines on the kingside.} Re8 15. Bd3 h6 16. e4 {mobilizing the central pawn majority} Bg4 17. e5 {this is premature; I should bring more pieces into play first, or (as shown by the engine) challenge the Bg4, which is Black's only good piece on the kingside at the moment.} (17. h3 {would help get the pesky bishop out of the way. For example} Bh5 18. e5 {now this pawn advance has more bite, since g4 is threatened and the bishop has no good square to go to. So} Bxf3 19. Rxf3 $18 { and White is rolling on the kingside with four pieces (queen, two bishops and rook) currently versus zero for Black.}) (17. Rb1 $5 {is a simple move that gets the rook in play and makes life more awkward for Black.}) 17... Be7 $2 { an obvious retreat but not a good one.} (17... Bf8) 18. Rb1 {a good move but not great.} (18. Bc4 $1 $18 {pinning the f-pawn causes major problems for Black, as now Qg6 is threatened.}) 18... Rb8 19. Be4 {right piece to move, but not the best square for it (per above). I thought for a while here on where the best spot for the bishop would be, but ultimately was too focused on queenside play, when in fact the big payoff is on the kingside.} Qd7 20. h3 Bxf3 (20... Be6 {is more solid.}) 21. Rxf3 $18 {with the f-file now open and two strong bishops pointing towards the king, along with the dominating central pawns, I have a major advantage.} Bd8 22. Rg3 {going for the somewhat cheap-looking, but still effective, threat of Bxh6.} (22. Qf2 $5) 22... Nxd4 23. Qd3 {seeking to avoid having to take on d4 with the pawn and then give Black ...Qxd4+. However, that would in fact be fine for White as well.} (23. cxd4 Qxd4+ 24. Kh1 Rxe5 {here I was too materialistic and thought that the three pawns for a piece wasn't a good deal for me.} 25. Bh7+ Kh8 26. Bb2 $18) 23... Rxe5 24. cxd4 Rh5 25. Bb2 {lining up against g7.} (25. Rxb7 $5 {would pursue a simpler winning strategy, based on my material advantage.} Rxb7 26. Bxb7 Bf6 27. d5 $18) 25... Bg5 26. Rf1 {now all pieces are in on the attack and the engine evaluates this as the equivalent of White having an extra piece and then some.} Re8 27. Qf3 $6 {a significant slip, since it would be much better to double the rooks on the f-file rather than leading with the queen. Also, the lack of a battery on the b1-h7 diagonal leaves me with fewer options for the bishop and allows Black's next move. I did not in fact have a concrete plan here.} (27. Rgf3 Bf6 28. Rxf6 $1 gxf6 29. d5 $18 {and Black's king is stripped of cover.}) 27... Rh4 {well played. Black now starts taking back some of the initiative by making his own threats, the first in a while.} 28. Bf5 Qb5 29. Qc3 {now I am responding more to Black's threats than looking for my own.} (29. Bd3 {would take advantage of the weakness on f7.} Qd7 30. Qxb7 $18) 29... Rf4 30. Rxf4 Bxf4 31. Rf3 $2 {missing the way to keep an advantage. The position is now equal.} (31. Bd3 $1 $18 {extracts the bishop with tempo, also saving the Rg3.}) 31... Qxf5 {by this point the game has fully turned around and Black is the one with all the threats. Psychologically this was a blow and I was tired of calculating variations, prompting the next error.} 32. g3 $4 { this in fact should now lose.} (32. Bc1 {is in fact the only move to preserve the draw, as it blocks Black's next.}) 32... Qb1+ 33. Rf1 Qxa2 $2 {allowing me to draw.} (33... Be3+ {should win for Black.}) 34. Rxf4 {at least I was able to correctly calculate the next sequence.} Re2 35. Rf2 Qb1+ 36. Bc1 Rxf2 37. Kxf2 $11 {now the engine evaluates the position as dead drawn.} Qf5+ 38. Kg2 Qe4+ 39. Kf2 Qf5+ 40. Kg2 Qe4+ 41. Kf2 1/2-1/2