Sunday, September 20, 2015

The changing tides of war

How quickly can the tides of war change? At Grandmaster level it usually remains stable: Once one side gets the advantage, he or she can often hold onto it until the opponent is outplayed. But at amateur level, blunders occur more frequently, leading to greater swings in advantage. Sometimes, both sides make so many mistakes that the tides of war change more than the number of times our MRT system breaks down.

Image from SGAG

Which is precisely what happens in one of my online games: I went into the middlegame with an extra pawn, only to see my advantage vanish when my opponent sacrificed the exchange for a strong attack. Several moves later... his botched attack evaporated, with the advantage back in my hands in the endgame. So sit back, and enjoy this whopping 70-move struggle.

Opponent vs Checkerboard 5
Correspondence Chess 2015

1. Nf3 Nf6
2. d4 e6
3. g3 b6
4. Bg2 Bb7
5. c4 Be7
6. Nc3 O-O
7. O-O Ne4
8. Qb3 d6
9. Qc2?!

Moving a piece twice in the opening is not a wise thing to do.

9... Nxc3
10. Qxc3 c5
11. Bf4 cxd4
12. Qc2?

White is losing a pawn for nothing. Better was: 12. Nxd4 Bxg2 13. Kxg2 e5?! Here perhaps White had been afraid of the pawn fork. However, he would realize after deeper calculation that he has a strong refutation: 14. Nf5! Qd7 (14... exf4 15. Qxg7#) 15. e4 Bf6 16. Be3 with nice piece placement and attacking chances against the weak pawn on d6.

12... Nc6
13. a3 (D)

Position after 13. a3

13... e5!?

Black is up a pawn, but it is not very well protected. I decided to exploit my temporary material advantage by going for a central advance. This move, however, weakens the light squares in the centre as well, and gives White a potential outpost on d5. Better would be to complete development first before attacking the centre: 13... Rc8 14. Rfd1 Bf6 15. Rac1 (15. e3? e5 trapping the bishop.) 15... Qe7 threatening ...e5 followed by ...e4 gaining space in the centre.

14. Bd2 f5
15. e3 e4
16. Nxd4 Nxd4
17. exd4 Bf6
18. Rad1?!

18. Bc3 {followed by Rad1 was better.

18... Qe7?

Missing the chance to win back the pawn. I seriously wonder how I managed to completely overlook 18... Bxd4 19. Bg5 Qxg5 20. Rxd4. The pawn on d6 looks weak, but after20... Qe7 21. Rfd1 Rf6 Black holds and even has the threat of ... Rc8 followed by ... d5

19. Be3 Rac8
20. b4 d5?!

Allowing White to push c5.

21. c5

Now Black is in real danger of allowing a passed pawn on the c-file.

21... Ba6
22. Rfe1 Bd3

22... Bc4 Cutting off the c5 pawn from one of its defenders was better.

23. Qc1 Qd7
24. Qc3 Qa4 (D)

Position after 24... Qa4

Planning to infiltrate the Queenside via the light squares. However, I was caught off-guard with White's next move.

25. Rxd3!

Sacrificing the exchange to open up the position. After I recapture, my pawn structure falls apart.

25... exd3
26. Bxd5+ Kh8
27. Qxd3 Rfd8
28. Qxf5

With the Queen and the Bishop pair, White gets a strong attack against my king.

28... Qxa3
29. Be4 Kg8
30. Qxh7+ Kf8
31. Bg6 Qb3 (D)

Position after 31... Qb3

Forced. 31... Qxb4? 32. Qh8+ Ke7 33. Bd2+ loses the Queen.

32. Qh3

Of course 32. Qh8+ Qg8 33. Qxg8+? Kxg8 takes most of the steam out of White's attack. Remember: When defending, you should seek piece exchanges to weaken the attack.

32... bxc5
33. bxc5 Rc7
34. Rb1 Qd5
35. Bf5 Re7
36. Bf4 Bxd4
37. Bd6 Rxd6!

Earlier on White sacrificed the exchange for his attack. Now, I can afford to return my extra material to weaken the attack by getting rid of White's bishop pair.

38. cxd6 Qxd6
39. Qh8+ Kf7
40. Qh5+ Kg8

40... Kf6? loses after 41. Qg6+ Ke5 42. Re1+ Kd5 43. Be4+ while 40... g6 41. Bxg6+ Qxg6 42. Qxg6+ Kxg6 leaves White with a two-pawn advntage in the endgame.

41. Bh7+ Kf8
42. Rd1?!

42. Bg6 threatening Qh8# was better.

42... Qf6

With White's bishop pair gone I can make counterthreats of my own.

43. Rf1 Re1!

With the threat of ... Qxf2+. White is forced to trade queens and abandon his attack.

44. Qf5 Qxf5
45. Bxf5 Re2 (D)


I could have chosen to trade rooks (45... Rxf1+ 46. Kxf1) and simplify into a drawn opposite-colour bishop endgame. However, I avoided the trade as I realized that the rook was very strong on the 2nd rank. Combined with the bishop pin it ties down White's king and rook to defending f2, while his bishop is of the wrong colour and unable to assist. Although I am down a pawn, my active rook and the outside passed pawn on a7 has swung the advantage back in my favour.

46. Kg2 Ke7

Activating the king. Notice that with White's king tied to defending f2, I am effectively a piece up in this endgame.

47. Kf3 Rd2
48. Bg4 Kd6
49. Kg2 a5
50. Bd1 Kc5
51. h4 Kb4
52. Bh5 a4

The outside passed pawn is a decisive factor.

53. Bf7 a3
54. Rb1+ Kc5
55. Rf1

Or 55. Rc1+ Kd6 where White must retreat to defending f2.

55... a2
56. Bxa2

Forced.

56... Rxa2
57. Rc1+ Kd5
58. Rf1 Ke4

Now my king goes over to support the g7 pawn.

59. Re1+ Kf5
60. Rf1 Kg4

Covering f3 and g3, reducing White's options. Winning the f-pawn is only a matter of time.

61. h5 Rc2

61... Kxh5 62. Kf3 also wins, but White has more freedom here with the threat of g4+

62. h6! gxh6 (D)

Position after 62... gxh6

White also has devious plans of his own. With the earlier exchange I am left with a rook pawn, which reduces my winning chances.

63. Rd1 Bxf2
64. Kh1 Bxg3

White is willing to lose his pawns now. If he is able to trade rooks, the game will be a draw: A rook-pawn, and a wrong-coloured bishop which does not cover the pawn's promoting square, cannot win if the enemy king controls the promoting square. Careful play is needed here if I want to win.

65. Ra1

65. Rd4+ Bf4 66. Kg1 might have offered more resistance, but White's king is still trapped on the 1st rank and has no way to successfully trade rooks.

65... h5
66. Rb1 h4
67. Ra1 Kh3
68. Rf1??

Losing on the spot, but other moves also hold no future.. For example 68. Rd1 Rh2+ 69. Kg1 Bf2+ 70. Kf1 Rh1+ 71. Ke2 Rxd1 72. Kxd1 Kg2 and even though White has removed the rooks from the board, Black controls the promotion square and will win.

68... Rd2
69. Rb1

69. Kg1 Rg2+ 70. Kh1 Bf2 71. Rxf2 (71. Ra1 Rh2#) 71... Rxf2 72. Kg1 Kg3 73. Kh1 Rf1#

69... Rh2+
70. Kg1 Bf2+ (D)
0-1

Position after 70... Bf2+

The threat here after 71. Kf1 is 71... Rh1+ winning the rook.

Sources:
http://sgag.sg/posts/6-potential-transport-minister-and-what-funny-things-he-she-would-say-if-the-mrt-breaks-down

Sunday, September 13, 2015

When not to exchange: Queenstown 2015

The last days of August 2015 were the first time I returned to the chessboard since giving up my pink IC. For those two days at Queenstown CC I stopped being a Private and became a commander instead...

Yelling at pieces that my grandma could run faster than them

The most memorable games of that tourney, however, were not my victories. It were the draws and defeats. For today, I will look at one of those games which I could have won, but ended up drawing due to a strategic blunder: Deciding to trade into an endgame prematurely, and leaving my passed pawn with little support.

Checkerboard 5 vs Opponent
44th Queenstown CC Open Chess Championships 2015

1. c4 Nf6
2. Nc3 g6
3. d4 d5
4. cxd5 Nxd5
5. e4 Nxc3
6. bxc3 c5
7. d5!?

With this the game steers towards very sharp, tactical waters.

7... Bg7
8. Qb3 e6
9. Bb5+! Kf8?!

I was expecting 9... Bd7 10. Bxd7+ Qxd7 11. dxe6 fxe6 12. Nf3 after which Black retains the right to castle but his king is still dangerously exposed.

10. Ba3

Continuing to hit the enemy king.

10... Qc7 (D)

Position after 10... Qc7

Let's do an analysis of this double-edged position. White is more developed, and his Queenside pieces are eyeing down on the Black king which is stuck in the centre. He also has the threat of creating a passed pawn should an exchange occur on d5. However, Black has his own threats. His bishop on the a1-h8 diagonal pins the c3 pawn, and White's Queen is temporarily overloaded looking after both c3 and d5. Here, I decided to consolidate my position first and complete development, since Black's king is stuck and won't be running away any time soon.

11. Rc1 a6
12. Be2

Better than 12. Bc4 b5 13. Be2 giving Black some tempo.

12... exd5?!

I did not consider this move to be best for Black, as it gives White the passed pawn without compensation. I looked at 12... Bh6 13. Rd1 Kg7 14. d6. For a moment it seems Black is in trouble, but after 14... Qc6 15. Bf3 Nd7 16. Ne2 (16. e5?! Qb5 and the e5 square is weak.) 16... Rf8 (D)

Position after 16... Rf8

Black has tucked his king to safety, activated his rook, and blockaded the passed pawn. His only weakness is the trapped light-squared bishop. Play will revolved around d6.

Returning to the main line after 12... exd5:

13. exd5 b5
14. Nf3 Kg8
15. O-O

Now White is clearly better. My plan is simple: Support the advance of the passed pawn, and use it to tie down Black's pieces.

15... Bb7
16. Rfd1 c4
17. Qb4 h5

Black's previous two moves indicate he wants to restrain my light-squared bishop, hindering it from supporting the passed pawn.

18. Qe7

Now I felt a better move was 18. d6 Qd7 19. Qa5 preparing Qc7 exchanging queens to open the file for my rooks. With the pawn on c7 the threat of Rd8+ would have been very dangerous.

18... Qxe7
19. Bxe7 Nd7

A good blockading piece against the passed pawn.

20. d6 Bh6

Position after 20... Bh6

21. Bg5?

Confident of my advantage, I erroneously decided on a series of minor piece exchanges. At first glance, it looks sound: With more pieces off the board, the advantage of the passed pawn will become more apparent. However, that is not so in this position: My passed pawn is far ahead in enemy territory with no friendly pawns to support it. Thus, transitioning into the endgame will deprive it of crticial piece support, making it easier for the opponent to pick it off.


Moreover, note that Black's pawn chain also provides a threatening outpost on d3, which might be important in the endgame. Always consider carefully before you exchange pieces!

Keeping the pieces on the board is better: 21. Rb1 Kg7 22. Ng5 Bc6 (22... f6 23. Ne6+ White is much better here.) 23. Bf3 (This exchange is justifiable as Black's light-squared bishop is a key defender of the position. Without it White's rooks have greater freedom of movement.) Bxf3 24. Nxf3 Rhe8 25. Rd5 (D)

Position after 25. Rd5

The d6 pawn is untouchable, granting White a significant spatial advantage in the endgame.

Returning to the main line after 21. Bg5:

21... Bxg5
22. Nxg5

Now Black's defence is much easier.

22... Kg7
23. Bf3

I looked at 23. Re1 Rhe8 24. a4 (Seeking to demolish the pawn chain and obtain more space for White's bishop.) f6 25. Nf3 bxa4 26. Nd2 Re6 27. Nxc4. Here White has more space for his pieces but Black threatens to double his rooks on the e-file. Notice the d6 pawn is blockaded and in urgent need of piece support.

23... Bxf3
24. Nxf3 Rhe8

Quickly denying White the chance to invade the e-file.

25. Re1 Nc5

Eyeing d7 and d3 at the same time.

26. Rcd1

After 26. Re7 Rxe7 27. dxe7 Re8 28. Re1 Kf6 Black still wins the pawn.

26... Rxe1+
27. Rxe1 Rd8
28. Rd1 Nd3! (D)
1/2-1/2


Occupying the outpost and cutting the d6 pawn from its guardian. Black has managed to equalize and even has a small advantage in the endgame. After a few more mistakes from both sides the game ended in a draw.

...

Lesson learned: Passed pawns need strong support, and always think twice before exchanging pieces!

Sources:
http://www.chessgraphics.net/
http://www.ww2aircraft.net/forum/aviation/gunther-rall-vs-zemkes-wolfpack-9247.html

Saturday, September 5, 2015

Euwe vs Alekhine, World Championship 1937

So it seems Lim Peh has decided to move aside your big tournaments for his beloved GE 2015. In that case, sit back, have some teh tarik, and enjoy this game from the World Chess Championship 1937.


Our heroes of the day are Max Euwe and Alexander Alekhine. Euwe had previously won the Championship title from Alekhine in 1935, and faced him again in a rematch 2 years later. The following game is one of Euwe's victories during the match; take note of the way he capitalizes on Alekhine's weaknesses to invade the Queenside and win the resulting endgame.

Alekhine (left) vs Euwe in 1937

1. d4 d5
2. c4 c6
3. Nf3 Nf6
4. Nc3 dxc4
5. a4 Bf5
6. Ne5!?

A peculiar way to recapture the pawn. In my opinion, it was better to recapture and develop at the same time with 6. e3 e6 7. Bxc4 Bb4 8. O-O O-O 9. Ne5 as in Capablanca - Euwe, Nottingham 1936, which was incidentally the previous game we looked at!

6... Nbd7
7. Nxc4 Qc7
8. g3 e5
9. dxe5 Nxe5
10. Bf4! Nfd7
11. Bg2 (D)

Position after 11. Bg2

11... f6?!

Protects e5 but weakens the e6 square. 11... O-O-O Bringing the rook into the action (with the possibility of ... Re8 defending the knight) is another possibility, but White will have to spend some tempi bringing his king
to safety.

12. O-O Rd8
13. Qc1 Be6
14. Ne4 Bb4

Euwe: "Black must castle as soon as possible, otherwise the weakness on the square, d6, would become dangerous."

15. a5

Euwe decides that a queenside breakthrough is his best course of action. An alternate plan is 15. Rd1 (eyeing the d6 square) O-O 16. Ncd6 Nb6! (16... Bxd6? 17. Nxd6 and White stands better.) 17. a5 Bxd6 18. axb6 axb6 with an unclear position; White is a pawn down but gets compensation with the open a-file, and Black's damaged pawn structure.

15... O-O

Hoping to win a pawn with 15... Bxc4? 16. Qxc4 Bxa5 doesn't work because of 17. Qe6+ Kf8 18. Nxf6! Nxf6 (18... gxf6 19. Bh6#) 19. Bxe5 Qb6 20. Bd6+ . Always watch out for tactics in games!

16. a6 (D)

Position after 16. a6

16... bxa6?

Euwe: "A move which, as a matter of fact, should not even be taken into consideration, as it seriously weakens the pawn position without compensation. Correct was 16... b6 17. Nxe5 Nxe5 18. Bxe5 (18. Qe3 was better.) 18... Qxe5! after which White could not play 19. Qxc6 because of Rc8 20. Qa4 Rc4!)

17. Nxe5 Nxe5
18. Nc5

Forcing an exchange that brings White's queen into the attack.

18... Bxc5
19. Qxc5 g5
20. Be3 Bd5

Alekhine seeks out exchanges to weaken Euwe's advance. However, the breakthrough is inevitable.

21. Rxa6 Bxg2
22. Kxg2

Euwe: "Avoiding the pitfall 22. Rxa7 Bxf1 23. Rxc7 Rd1 after which White would get into trouble."

22... Rf7 (D)

Position after 22... Rf7

23. Rfa1

Euwe: "And not 23. Rxa7 Qxa7 24. Qxa7 Rxa7 25. Bxa7 allowing Black to equalize by Rd2 "

23... Qd6
24. Qxd6 Rxd6
25. Rxa7 Rxa7
26. Rxa7

Now White is a pawn up. However, careful play is still needed to convert his advantage in the endgame.

26... Nc4
27. Bc5 Re6
28. Bd4 Rxe2
29. Bxf6 g4
30. Kf1 Rc2

Black still wins the pawn after 30... Re4 31. Rg7+ Kf8 (31... Kh8?? 32. Rxg4#) 32. Rxh7

31. Rg7+ Kf8
32. Rxg4 Nxb2
33. Bxb2 Rxb2 (D)


Simplifying into a rook endgame. Had Black's c6 pawn been on g6 instead, it would have been a 3 vs 2 draw. However, White can now convert his kingside pawn majority and go for a win.

34. Rc4 Rb6
35. Ke2 Kf7
36. Rh4 Kg6
37. Rf4!

Cutting off Black's king.

37... Rb3
38. Rc4 Rb6

Notice how Black's outside passed pawn, instead of being an advantage, becomes a weakness in this position. Black would like to centralize his king and keep his rook active, but the rook is tied down to defending the pawn instead.

39. Ke3 Kf5
40. g4+ Ke6
41. f4 (D)

Position after 41. f4

White begins to convert his majority.

41... Kd5
42. Rd4+ Ke6
43. f5+ Ke7
44. Re4+ Kf7
45. h4 Rb1
46. Kf4 Rc1

46... Rf1+ 47. Kg5 is still winning for White.

47. Ra4 h6
48. Ra7+ Kg8
49. g5 Rc4+
50. Ke5 (D)
1-0

Position after 50. Ke5

50... Rxh4 51. g6 wins the game.

Fantastic play from Dr Euwe! Unfortunately for him, Alekhine eventually won the match and regained control of the world crown.