Thursday, November 27, 2014

Christmas Presents! (Part 1)

Ok I know Christmas is still a month away, but you guys probably can't wait till then to receive your presents... so I've prepared some early ones for you. Don't worry; they're not difficult (:

Puzzle 1: Black to move

Puzzle 2: White to move and mate in 2

Puzzle 3: Black to move and mate in 2

Puzzle 4: Black to move and mate in 4

Puzzle 5: White to move

Puzzle 6: White to move and mate in 2

Puzzle 7: Black to move and mate in 4

Puzzle 8: White to move and mate in 2

Have fun! (:

Tuesday, November 25, 2014

Rook-Pawn endgames: Four vs Three

Miss our old friend? Well then, welcome back to another episode of rook endgames (:

Previously we left off in a Rook + Three pawns vs Rook + Two position. Today, we will wrap this up by extending to a Four vs Three:

A common position

Anyone with sufficient tournament experience would have encountered positions this several times in their career. Here, the stronger side (White in this case) wants to use his pawns to grab as much space as possible, creating the "squeeze" position we've investigated in the Three vs Two case (see http://nushsblackknights.blogspot.sg/2014/10/rook-pawn-endgames-three-vs-two-part-1.html). Thus, White to play will not hesitate to play 1. g4! to stop ... h5 and ... f5 (which would destroy Black's pawn structure after the exchange) and gain space in the middle with Kg3, h4 and f4. While Black still has drawing chances, his defensive task will become very difficult.

For the defender, his goal will be to prevent this horrific "squeeze" from occuring. As such, he must deny the opponent space in the centre with the same set of guidelines we've been using: Keep the rook active, and go for pawn exchanges that do not severely weaken the pawn structure. Going by this he should be able to safely trade to a Three vs Two, then a Two vs One, and finally a Philidor/Inverse Philidor position.


1... h5!

Stops White from playing 2. g4; now 2. h3 followed by 3. g4 will lead to a pawn trade favourable for Black.

2. h3 Rc2

Keeping the rook on the b-file continues to tie White's king to the f2 pawn.

3. g4 hxg4

One down, two more to go.

4. hxg4 g5

Now any advance of the f pawn will lead to another exchange.

5. Rb3

Or 5. Kg3 Rc3 where Black's active rook continues to annoy White.

5... f6
6. Kg3

6. Rb7+ Kg6 doesn't get White anywhere

6... Kg6
7. f4 gxf4+
8. exf4 (D)

Position after 8. exf4

Recapturing with the e-pawn gives White the best winning chances; 8. Kxf4? creates split pawns that offers no hope of victory (e.g. 8... Rf2+). Now we have a Two vs One position.

8... Rc1
9. Rb7

Preparing to push the f-pawn; the immediate 9. f5+ Kg5 gives White no progress.

9. Rb6 is an interesting alternative and Black must be careful of the pin here: 9... Kf7 (9... Rg1+ 10. Kf3 Rf1+ 11. Ke3 and Black must be careful not to play 11... Rg1? because White wins by exploiting the pin after 12. g5!)10. g5 fxg5 11. fxg5 and he should be able to hold out the resulting Philidor Position.

9... Rg1+
10. Kh3

10. Kf3 Rf1+ 11. Ke3 and Black can safely play 11... Rg1 here because there's no pin now!

10... Rh1+
11. Kg2 Ra1

Threatening to cut off White's king by 12... Ra3

12. f5+ Kg5
13. Rg7+ Kf4 (D)
1/2-1/2

Draw

...

From the above example we can see that pawn exchanges usually do not help the stronger side. So to repeat my point, his main hope for a win lies in gaining space in the centre with his pawns, something which the weaker side must prevent. We will take a look at another example:

Another typical position

Once again, White to play would go for the space gaining 1. e4! , discouraging 1... f5 and preparing for the "squeeze". While Black can still draw here with 1... Ra3 (fencing off White's king), his defensive task here will not be easy.

That said, Black to move is simple: 1... f5! ensures that White will not be able to gain sufficient space in the centre.


1... f5!
2. Kf3 Rc2

Black is happy to keep his rook active on the 2nd rank.

3. Kf4

White has to go all in, otherwise Black will continue shuffling his rook on the 2nd rank.

3... Rxf2+
4. Kg5 Rg2
5. Kxg6 Rxg3+
6. Kxf5 Rxe3
1/2-1/2

After all the pawns fall both sides can call it a day.

...

Note that at this stage, I no longer emphasize on memorization of positions as compared to the past; ideas like the Lucena, Philidor and Vancura positions should already be firmly embedded in memory. Thus in complicated rook-pawn endgames, all it takes is a few simple guidelines and a consultation of your endgame "database" (your memory!) to chart your way through seemingly complex waters. Remember: It's about concept, not memorization!

That said, let us recap the pointers to look out for in a rook-pawn endgame where pawns are on one side of the board. When the stronger side is one pawn up, his task is to:

  • Use his pawns to gain central space so as to cramp up his opponent
  • Avoid pawn exchanges until he gets a dominating position
  • Try to get a passed pawn
  • Create a winning king-pawn endgame/Lucena Position

For the weaker side, he can prevent this using the following:

  • Avoid trading rooks unless it creates a drawish pawn endgame
  • Keep his own rook active by using it to tie down the enemy king
  • Deny the opponent's pawns any central space with his own pawn pushes
  • Put his king in front of the enemy pawns (to prepare for an upcoming Philidor/Inverse Philidor)

If that's too much for you to remember... then just take note (nope, not making any references here): Active play good, passive play bad!

Two vs One: http://nushsblackknights.blogspot.com/2014/09/rook-pawn-endgames-two-vs-one.html
Three vs Two (Part 1): http://nushsblackknights.blogspot.com/2014/10/rook-pawn-endgames-three-vs-two-part-1.html
Three vs Two (Part 2): http://nushsblackknights.blogspot.com/2014/10/rook-pawn-endgames-three-vs-two-part-2.html

Sources:
"Silman's Complete Endgame Course" by Jeremy Silman

Wednesday, November 19, 2014

The Tiger of Madras: World Chess Championship 2014 Game 3

Starting from next year onwards, I will be posting fewer articles due to NS commitments. I do hope that our new admins will be able to take over the responsibility and keep this page alive. Compared to other CCA blogs which only broadcast announcements, ours is one of the few which provides training material to facilitate learning outside the classroom. It is an asset which we should all treasure and make full use of.

I'm sure many of us would be following WCC 2014 closely, so we all know what happened in Game 3: Anand levelled the score by defeating Carlsen for the first time in 4 years. Let's take a look at this historic game:

Anand, Viswanathan vs Carlsen, Magnus
World Chess Championship 2014 Round 3


1. d4 Nf6
2. c4 e6
3. Nf3 d5
4. Nc3 Be7
5. Bf4 O-O
6. e3 Nbd7
7. c5 c6
8. Bd3 b6
9. b4 a5
10. a3 (D)

Position after 10. a3

The players go for a line in the Queen's Gambit Declined, where White enjoys plenty of space on the Queenside.

10... Ba6

Black's previous moves were directed towards exchanging this bad bishop for White's good counterpart.

11. Bxa6 Rxa6

Now if Anand wanted to play safe, he could continue with something like 12. O-O. But here he was playing for a win, and thus lashed out with a bold move:

12. b5!?
12... cxb5
13. c6 Qc8

If 13... Nb8? then 14. c7 is crushing. Black has to exploit the pin on the c-file.

14. c7 (D)

Position after 14. c7

So much for a "solid" Queen's Gambit! White is a pawn down, but he has a monster passed pawn on c7 which will be the bane of Carlsen for the rest of the game. As for Black... well, let's say the Queen is the last piece in the world which you'll want to use as a blockader.

14... b4
15. Nb5

Reinforcing the passed pawn. It will not be good to accept the capture: 15. axb4 Bxb4 and the intruding bishop poses problems.

15... a4

This move clears the way for ... Ra5 attacking the knight, and also prevents a possible a4 advance by White which will make the knight untouchable.

16. Rc1

White would love to put a minor piece on the d6 square, but he cannot do that immediately because it gives up protection of the c7 pawn. Hence 16. Rc1 adds an extra defender that allows White to threaten Nd6.

16... Ne4
17. Ng5 Ndf6

The knight is not free; 17... Bxg5 18. Bxg5 Nxg5? leads to the crushing 19. Nd6 where it's all over.

Carlsen spent nearly 30 minutes thinking about 17. Ndf6, an indication that he was venturing into unfamiliar territory. On the other hand, Anand was well prepared and spent less time on his moves (during the press conference, it was revealed that he had analyzed this position as far as move 20!)

18. Nxe4 Nxe4?!

While it looks logical, 18... Nxe4 is a slight inaccuracy; Black would have been better off recapturing with the pawn and giving his knight access to the d5 square: 18... dxe4 19. Nd6 Bxd6 20. Bxd6 b3 21. Bxf8 Kxf8 22. Qd2 Nd5 and Black's powerful knight gives excellent compensation for the exchange.

19. f3 Ra5

Once again 19... Nf6? 20. Bd6 Bxd6 21.Nxd6 wins for White.

20. fxe4

In an earlier game (Aronian vs Adams, Bilbao 2013), White defended the knight with 20. Qe2 and after 20... Qd7 21. fxe4 Rc8! 22. exd5 exd5 23. axb4 Rxb5 Black was able to hold the draw.

20... Rxb5
21. Qxa4 Ra5
22. Qc6 bxa3 (D)

Position after 22. bxa3

Black tries to generate some counterplay with a passed pawn of his own. However, White's pawn is more advanced and ties down the enemy Queen, while his own Queen is free to roam about.

23. exd5 Rxd5

A difficult decision; 23... exd5 damages the pawn structure and creates a weak pawn on d5. While 23... Rxd5 avoids this problem, it strips the a-pawn of protection.

24. Qxb6

Now the Black rook cannot return to the a-file.

24... Qd7

Changing of the guard; Carlsen tries to get his other rook into the game.

25. O-O?!

For a moment it seemed that Anand was letting his opponent off the hook. The better variation was 25. Qa6 Rc8 26. Rb1! where Black is forced to give up the exchange in order to survive: 26... Rxc7 27. Rb8+ Bd8 28. Bxc7 Qxc7 29. Rc8 and White wins.

25... Rc8
26. Rc6 (D)


Black is completely tied up here; his heavy pieces have no good squares to go to, and he cannot trade bishops on d6.

26... g5
27. Bg3


27. Be5 was another move worth considering; Black cannot push f6 because of the rook on f1.

27... Bb4!

Exploiting the fact that 27. Bg3 weakened the e3 pawn.The threat here is that if White tries doubling rooks with 28. Rfc1, then 28... Bd2 picks up the pawn. After some thought, Anand answered this move with an equally strong reply:

28. Ra1!

Now if Black plays Bd2 he cannot take on e3 after Rxa3. At the press conference, Anand commented that he was very happy with this move.

28... Ba5?

Under time pressure, Carlsen finally cracks. 28... h5 would have offered more resistance, but after 29. h3 h4 30. Bh2 Kh7 31. Ra2 (preventing 31... Bd2) Black has no source of counterplay.

29. Qa6 Bxc7 (D)

Find the best move for White
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30. Qc4!

The pin is decisive. Carlsen had been hoping for 30. Qb7 Rxd4! 31. exd4? Qxd4+

30... e5
31. Bxe5 Rxe5
32. dxe5 Qe7
33. e6 Kf8
34. Rc1 (D)
1-0

Position after 34. Rc1

Faced with an untenable position with only seconds remaining on his clock, Carlsen throws in the towel. Further resistance will only lead to major loss of material.

...

So it is clear that the Tiger of Madras still has plenty of fight left in him. Through this game we can witness a display of Anand's strengths: Superior opening preparation (which enabled him to lure Carlsen into unfamiliar territory), good calculative skills, and an uncanny ability to fight in dynamic tactical positions.

At the time of writing the score is 3.5-4.5 in favour of Carlsen. Round 9 starts tomorrow, and with each successive game we would expect both players to put up an even greater fight. So sit back, grab some popcorn a chess engine, and enjoy the remainder of this exciting match!



Sources:
https://www.youtube.com/watch?v=4AOvrqCSzsA
https://www.youtube.com/watch?v=4AOvrqCSzsA
https://www.facebook.com/ChessMemes2371

Thursday, November 6, 2014

World Chess Championship 2013: Game 9

With the World Chess Championship 2014 set to open tomorrow, it would only seem fitting if I were to analyze one of the games from the WCC 2013. Here I will pick Game 9, which was a double-edged and highly exciting game where Anand was going all out for a win. Unfortunately, he gave way under immense pressure, blundered and had to resign instead.

WCC 2013: Clash of the titans

Anand, Viswanathan vs Carlsen, Magnus
World Chess Championship 2013


1. d4 Nf6
2. c4 e6
3. Nc3 Bb4
4. f3 d5
5. a3 Bxc3+

The variation 5... Be7 6. e4 dxe4 7. fxe4 e5 8. d5 keeps the bishop pair, but allows White to build a large pawn centre.

6. bxc3 c5
7. cxd5

With 4. f3 White's plan was to push e4 and gain central space, hence Black's last move was aimed against d4 so as to delay e4. After 7. e4 dxe4 Black's Queen increases the pressure on d4.

7... exd5
8. e3 c4!?

A very interesting move ("ambitious"-- Daniel King) by Carlsen. By advancing this pawn Black has several goals in mind: (1) To deprive White's light squared bishop of the e3 square, (2) To create a potential outpost on b3 with the maneuver Nc6-Na5-Nb3, and (3) To prepare his queenside pawn majority for a general attack. The downside to this move, however, is that it relieves the pressure on d4, allowing White to safely play e4 and hit Black's weak pawn on d5.

9. Ne2 Nc6
10. g4 O-O
11. Bg2 Na5
12. O-O Nb3
13. Ra2 b5
14. Ng3 a5 (D)

Position after 14. a5

We see action across the entire board: White threatens to roll his pawns over the kingside, before swooping in his pieces with the ultimate goal of mate on g7. In return, Black seeks counterplay on the Queenside, and hopes to use his pawn majority to create a passed pawn on that wing. Moreoever, his last move not only sets the pawns in motion, but also allows for ... Ra6 later on as a possible defense on the kingside. Fireworks on the kingside, centre, and queenside; who wouldn't want to watch such an exciting game?

15. g5

In post-analysis the sacrificial line 15. e4 dxe4 16. fxe4 Bxg4 17. Qe1 was proposed, but after 17... Ra6 White has the better chances.

15... Ne8
16. e4 Nxc1

Notice that all this while Black had been letting his knight sit calmly on b3 rather than exchanging it straightaway. The reason is simple: His knight was much better than White's bishop, which was trapped by his own pawns. However, after 16. e4 the bishop's path is opened and has potential to create trouble on the kingside, so Black eliminates that threat.

17. Qxc1 Ra6
18. e5 (D)

Position after 18. e5

18.... Nc7

Carlsen spent more than 20 minutes on this move; he admitted that he felt nervous after 18. e5. At the press conference he pointed out that while the variation 18... g6 exploits the weak f5 square after the e5 advance, he did not like the position after 19. f4 Ng7 (aiming for 20... Nf5) 20. Rb2 Rb6 21. Qb1, where Black can aim at b5 and f5. Following 21... Qd7 22. f5 Nxf5 23. Nxf5 gxf5 24. Bh3! Black's dual weaknesses on b5 and f5 do not look appealing.

Another proposed variation is 18... f5 but after 19. gxf6 gxf6 20. f4 Black's kingside is dangerously exposed.

19. f4 b4
20. axb4 axb4
21. Rxa6 Nxa6 (D)

Position after 21... Nxa6

Black is about to get a passed pawn on the Queenside. However, his knight is now miles away from the king... not a good place to be in especially when the enemy pawns are about to storm the kingside!

22. f5

Anand's vigorous attack is characteristic of his playing style in his youth.

22... b3
23. Qf4

Played after 45 minutes of thought. 23. f6 g6 24. Qf4 Kh8 25. Qh4 isn't fast enough because of 25... Rg8/25... Nc7.

23... Nc7
24. f6 g6
25. Qh4 Ne8

The knight comes back just in time to prevent mate on g7. The other candidate move 25... Ne6? also defends g7, but the knight is vulnerable to enemy pieces: e.g. 26. Bh3 Qc7 27. Qh6 Bb7 and all might seem safe after 28. Bxe6 fxe6 since the Queen now defends g7. However, White's Bh3 is not just to chase away the knight; it also helps to sink his own knight into f5! So after 28. Nf5! (threatening 29. Ne7 followed by 30. Bxe6) 28... Re8 (28... gxf5 29. Bxf5 Re8 30. Qxh7+ Kf8 31. Qh8#) 29. Nd6 Black's position is simply falling apart. Hence, 25... Ne8 ensures that the knight remains safe from all these problems.

26. Qh6 b2

Strong counterplay by Carlsen; now the rook lift is answered by a promotion with check.

27. Rf4 b1=Q+ (D)

Position after 27... b1=Q+

Black has two Queens, but the threat of getting mated on h7 (after Rh4) is very dangerous. After 28. Bf1, the best defence here is 28... Qd1! 29. Rh4 Qh5 30. Nxh5 gxh5 31. Rxh5 Bf5! 32. Bh3 Bg6 (not 32... Qd7? 33. g6!) 33. e6 Nxf6 (Black gives back his extra material to protect his king) 34. gxf6 Qxf6 35. Re5 fxe6 36. Qe3. Here Black is a pawn up, but White still has his chances since the e5 pawn is weak.

Instead, Anand made an inexplicable blunder:

28. Nf1??

Totally overlooking the fact that moving the knight clears the e1-h4 diagonal for the Queen.

"When I got to this position, I suddenly saw [28. Nf1 Qd1 29. Rh4 Qh5 20. Rxh5 gxh5 21. Ne3] and the knight is coming to e7. By a miracle, black will probably play Be6, for Bxd5 he might have to play Qxd5. For a second I got excited. The problem, I missed the knight which was on g3 has just moved. As soon as I put the knight on f1 I knew what I had done. What can I say?"
-- Vishy Anand, Game 9 Press Conference

28... Qe1
0-1

Anand simply resigned, for after 29. Rh4 Qxh4 30. Qxh4 White has no more attack, and ends up a rook down.

...

While we might sit comfortably in front of our computers and criticize Anand's mistake, one must not forget that under those circumstances-- the stakes at an all time high, with the world watching you-- one can hardly imagine the immense pressure faced by both players. To reinforce this, here are two statements made by Carlsen during the Q&A session of the press conference:

Q: (Amit Karmarkar, The Times of India) Magnus, it was quite tense today. Can you describe the tension you were going through? 

A: (Magnus Carlsen) It was really tough game. From the opening it was clear it going to be unbalanced. And I run a serious danger of getting mated which I hadnt in previous games. I had to deal with the situation. I had to create counterplay. It was really tough game. 

Q: (FIDE Press Officer) Were you scared in any particular moment in this game? 

A: (Magnus Carlsen) Basically all the time. The white pawns look extremely menacing. At the same time I was trying to calculate this as well as I could. I did not find a forced mate. It seems there wasn't any mate. At least no obvious one.

At the end of the day, it all depended on who could remain more calm under those circumstances and outlast his opponent. Carlsen's tenacity allowed him to do that, and he eventually clinched the world title with a 3 point lead.

But definitely, the Anand that Carlsen will be facing in a couple days time will be a much better person than the Anand of 2013. He will be more well prepared, and ready to fight it out more aggressively. So it seems that an exciting 3 weeks of WCC 2014 awaits us!



Sources:
https://chessmusings.wordpress.com/category/correspondence-chess/
http://www.theweekinchess.com/chessnews/events/fide-world-chess-championship-anand-carlsen-2013/carlsen-on-the-brink-of-becoming-world-chess-champion-after-game-9-win
https://www.youtube.com/watch?v=sK5l7SRRN9c
https://www.youtube.com/watch?v=Ww_qifR3ajI
https://www.facebook.com/ChessMemes2371

Monday, November 3, 2014

The art of patience: Spassky vs O' Kelly, San Juan 1969

Well I hope your exams all went well! As a post exam treat I'll pause our study of rook endgames for a while and take a look at this interesting game. You will witness an impressive and meticulous preparation by Boris Spassky in order to execute his plan in the middlegame.

Boris Spassky vs Alberic O'Kelly de Galway
San Juan (Puerto Rico) 1969


1. e4 e6
2. d4 d5
3. Nc3 dxe4
4. Nxe4 Bd7
5. Nf3 Bc6

The Fort Knox variation solves the problem of Black's light-squared bishop in the French. But the downside is obvious: A loss in tempo.

6. Bd3 Bxe4

6... Nd7 is more common.

7. Bxe4 c6
8. O-O Nf6
9. Bd3 Nbd7
10. c4 Bd6
11. b3 O-O
12. Bb2 Qc7
13. Qc2 Rfe8
14. Rfe1 Bf8

15. Rad1 g6 (D)

Position after 15... g6

White has completed his development and enjoys a lot of space in the centre. However, Black's position is extremely solid, and will not be easy to break through. Now, Spassky decides on a plan involving a d4-d5 push. However, before he can achieve this, he needs to go through extensive preparation and redevelopment (moving developed pieces to better squares) before pushing d5. The breakdown of his preparation is listed as follows:

Step 1: Redeploying the light-squared bishop to another square so that it does not block the d-file.

16. Bf1 Bg7
17. g3 Rad8
18. Bg2 Nh5

Step 2: Placing the rooks in an optimal position for mobility after d4-d5; in this case doubling them on the e-file.

19. Re2 Rc8
20. h4 Rcd8
21. Rde1 Nhf6

Step 3: Redeploying the Queen to exploit the a1-h8 diagonal, which will be opened after d4-d5.

22. Qc1 h5 (D)

Position after 22... h5

Notice Black is passing time here since his position looks solid enough. The dubious variation 22... Qa5 23. Bc3 Qf5? 24. Re5 Nxe5 25. Rxe5 Qd3 26. Ne1 Bh6 27. Nxd3 Bxc1 28. Nxc1 only leaves Black with an exchange down.

23. Bh3 Nf8
24. Qa1 Ng4

After something like 24... N8h7 White also has the option of playing 25. Ne5, in preparation for c5 followed by Nc4-Nd6.

25. Bc3 Nh6
26. Qb2 Nf5?

You will see why this is a mistake later. On the other hand, after 26... Nd7 27. Ng5 Ng4 White will need further preparation (e.g. 28. Bg2) before he can push d5.

27. Bxf5 gxf5
28. d5! Bxc3
29. Qxc3 cxd5
30. Nd4! (D)

Position after 30. Nd4

The recapture on f5 (hence why Nf5 was a mistake) allowed White to unearth a tactical threat. After 30... dxc4 31. Nxf5 White threatens to win a rook or mate on g7.

30... Qd7
31. c5 Nh7
32. b4 a6
33. a4 Rc8
34. b5 axb5
35. axb5 Rf8
36. c6 bxc6

White's d5 plan cost him a pawn, but gave a passed pawn in return.

37. bxc6 Qd8
38. Rc1 Nf6
39. c7 Qd7
40. Qe3 Ne4
41. f3 e5
42. fxe4 f4
43. gxf4 exd4
44. Rg2+ (D)
1-0

Position after 44. Rg2+

The kingside attack decides matters.

...

So we've seen that sometimes, patience and extensive preparation is needed when it comes to realizing a plan in the middlegame, even one as simple as pushing a pawn. In this case, Spassky's efforts paid off after his d5 push gave him a passed pawn, tying down O'Kelly's pieces so badly that a frontal attack quickly ended the game.

Sources:
"Pawn Structure Chess" by Andrew Soltis