Saturday, October 29, 2016

Deepavali/Halloween tactical presents 2016

Wishing all our Hindu friends a happy Deepavali!



Trick or treat!

Saturday, October 22, 2016

A curious pawn race: Discussion

I guess I've given y'all enough time. Let's take a look at the puzzle again:

White to move and promote his pawn first

To solve this puzzle you need to understand two main concepts of pawn endgames. The first is the pawn majority:

White has the pawn majority

In the above position White has a pawn majority. All he needs to do is push 1. c5, and will get a passed pawn regardless of whether Black captures or declines.You want to use your pawn majority to create a passed pawn and promote first.

Suppose in that same position White decides to be a patzer and pushes 1. b5??. This leads us to our next concept, the pawn freeze:

Pawn freeze: Black's single pawn stops two of White's

This is a position you don't want to get as White: He cannot push his backward c-pawn, as that would give Black a passed pawn. By using only one pawn Black can tie down both of White's. Take note!

So in our puzzle, White needs to advance his queenside pawn majority to make a passed pawn before Black does. At the same time, he has avoid creating any pawn freeze positions against his majority. Let us first look at the underlying idea, by assuming that Black is cooperative:

(NOTE: In the following diagrams, please assume both kings are non-existent; they are only there to ensure a legal position)


That was easy... all White has to do is advance his pawn majority, winning since he has the first move. But Black has methods of countering this! See the next example:



This was what we gone through just now: The deadly pawn freeze, where one enemy pawn stops two of yours. Make sure you don't get into such a situation, otherwise your pawn majority is as good as useless!

Image from Quickmeme.com




So how is White going to get that tempo back? One way would be to copy Black's counterplay in Example 2!


So we see why this puzzle is so tricky: White needs to make sure his pawn majority is able to advance properly without getting into pawn freezes. At the same time, he needs to stay ahead in tempo.

Now that we have solved the puzzle, I leave the next one as a challenge to y'all; remember the concepts you learned earlier, and apply it below.



Have fun!

Saturday, October 15, 2016

A curious pawn race

A couple of weeks ago I came across the following puzzle, which I will like to share with y'all:

White to move and promote his pawn first

The rules were simple: White to move. Whichever side could promote a pawn first would win the challenge.

At first glance it looks easy: White has the first move, so obviously he can advance his queenside pawn majority to create a passed pawn first. But once you factor in the possible responses by Black you will realize that it isn't that straightforward! There are many endgame concepts to take into account, such as pawn majority, tempo, pawn freeze, and others.

Hence, I am leaving this puzzle as a challenge for y'all to work on. You are free to speculate on the moves and possible replies in the comments section, and I will go through the solutions next week.

Have fun!

Sunday, October 9, 2016

Pre-Exam Presents 2016

Just some last bit of fun before the exam.





Have fun!

Wednesday, October 5, 2016

Returning the gaunlet: Mamedyarov vs Gelfand, Tal Memorial 2016

At the time of writing, the Tal Memorial has just concluded its 7th round, with peaceful draws across the entire field. But it wasn't always peaceful across the entire tournament, especially Round 6 which saw 4 decisive games.

Today we will look at a short game from Round 2 between Mamedyarov and Gelfand. In this game, White sacrificed a pawn to gain a strong attack against the enemy king. While Mamedyarov made it look easy, it was only because Gelfand underestimated the strength of the attack and accepted the sacrifice.

But alas, it shows how strong the temptation is to grab pawns and neglect development in the opening. Be warned!

Mamedyarov, Shakhriyar vs Gelfand, Boris
Tal Memorial 2016

1. d4 Nf6
2. c4 e6
3. Nf3 d5
4. Nc3 c6
5. Bg5

5. e3 is a popular choice, building a solid centre at the cost of blocking the light-squared bishop.

5... h6
6. Bxf6?!

I don't know what was the purpose behind giving up the bishop pair so willingly, the only plausible reason being that retreating the bishop cedes tempo to Black. (6. Bh4 Be7 7. e3)

6... Qxf6
7. g3 Nd7
8. Bg2 dxc4
9. O-O Be7
10. Ne4 Qf5
11. Ned2 e5

Freeing the light-squared bishop.

12. e4 Qh5?!

I don't find it wise to hang the queen, especially when you are behind in development. 12... Qe6 {followed by ...0-0 and ...Re8/Rd8 reinforcing the centre was better.

13. Nxc4 exd4
14. Qxd4 Qc5

Notice that Black has moved his queen four times in the opening!

15. e5 O-O (D)

Position after 15... O-O

White has a clear advantage here: His pieces are centralized, while the e5 pawn hampers Black's ability to catch up in development. Naturally, White should not trade queens and instead look for ways to attack.

16. Qe4

16. Qxc5? Nxc5 lets Black equalize.

16... Nb6
17. Ne3 Qb4

Black's challenge is clear: Trade queens, or retreat your own queen to protect the pawn. Either way Mamedyarov is forced to slow down his attack. A dilemma indeed, but based on the assumption that the pawn needs protection in the first place!

Black could develop normally with 17... Be6 18. Nd4 Bd5!? 19. Nxd5 Nxd5 equalizing comfortably. While 20. e6 looks dangerous, Black can simply ignore it and counterattack: 20...  Bf6 (20... fxe6?? 21. Nxe6) 21. Rad1 Bxd4 followed by fxe6 liquidating the attack.

18. Nd4 (D)

Position after 18. Nd4

Returning the gaunlet: You wanted the pawn, so take it!


18... Rd8
19. Rad1 Qxb2?

Challenge accepted. Gelfand must have forseen the attack that followed, but felt confident that he could hold it off.

19... Nd5 20. Nef5 Bxf5 21. Nxf5 Qxe4 22. Bxe4 {rading into the endgame, although White still has a slight edge with his active pieces.

20. e6! Bxe6
21. Nxe6 fxe6 (D)

Position after 21... fxe6

Black's light squares are fatally weakened.

22. Bh3 Kh8
23. Bxe6 g5?

Think twice before pushing pawns! This move only weakens the kingside.

Was it not better to simplify when being attacked? 23... Rxd1 24.Rxd1 Bc5 25. Ng4 Rf8 is a good counterattack that keeps White on edge.

24. Ng4 Rxd1

Simplifying, but the damage to the kingside has already been done.

25. Rxd1 Qg7
26. Ne5 Qf6
27. Bb3!

Relocating the bishop to the b1-h7 diagonal.

27. Nf7+ Kg7 White can't make progress with the Black queen in the way.

27... Kg7
28. Ng4 (D)
1-0

Position after 28. Ng4

White's control over the light squares prove crushing.

28. Ng4 Qf8 29. Bc2 the constant mate threats force Black to eventually give up material: Qf7 30. Ne5 Qg8 31. Nd7 Nxd7 32. Qxe7+ Qf7 33. Rxd7 with a winning endgame for White.

Thus shows the danger of sacrificing development to grab pawns; even strong players can give in to the temptation!