Monday, November 30, 2015

Basic Rook vs Minor Piece Endgames: Part 3

It's about time I release the solutions to our earlier challenge. Trust me, they're really simple:

Position 1: White to move and win

The tricky part here is to trap Black's king in the same coloured square as his bishop -- in this case the corner a8. Once this is done, the rest is manageable so long as you have revised on Part 1. To trap the enemy king, a team effort by king and rook is necessary:


1. Rb6+ Ka7

Otherwise the bishop is left hanging.

2. Kc6 Bd3
3. Kc7 Bh7

Of course Black could move the bishop to any other square, but White still wins so long as he employs the same method: Driving the bishop to the a-file.

4. Rh6 Bg8
5. Rg6 Bh7
6. Rg7 Be4

Now the rest is easy, if you have studied Part 1.

7. Rg4 Bc2
8. Rg2 Bb3
9. Rg3 Ba4
10. Ra3
1-0

Winning the bishop and the game.

Position 2: Black to move and win

In Position 2 the knight is on the side of the board but not in the corner. Black's king guards one of the escape squares g4, so Black's rook must find a way to cut off the other 3 escape routes and trap the knight. With this in mind, finding the correct move becomes a piece of cake:

1. Rf8! Kd4
2. Kg5
0-1

And Black wins the knight and the game.

...

Easy, wasn't it? Of course, we are talking about basic rook vs minor piece endgames... games with more pieces and pawns won't be so straightforward! But at least we won't be talking about them over here... or will we? (:

Friday, November 27, 2015

Basic Rook vs Minor Piece Endgames: Part 2

In Part 1, we saw how the bishop was able to hold up against the rook in the endgame. Today, we will see how the knight fares. Welcome to the Rook vs Knight endgame.

Image from cartoonstock.com
Rook-Knight endgames might look tricky, as the knight does not possess the long range powers of either the bishop or the rook. However, there is a simple guideline to determine whether the battle ends in a win or draw. Take a look at the position below:


The guidelines are as follows:
  1. If the knight is in the corner of the board (Red Zone), the attacker can trap the knight with his rook and king to win the game
  2. If the knight is at the side of the board (Yellow Zone), the attacker only has some chances to trap the knight
  3. If the knight is in the centre of the board (Green Zone), the defender has good chances to draw with correct play

Let us see how this works. Take a look a position where the knight is in the corner (Red Zone):

A knight on the rim is dim

Black's knight has been driven to the corner, and the escape squares e7 and f6 are guarded by the king. All White need to do is to play 1. Rh5 taking away the last escape square h6, before moving in with 2. Kf7 to win the knight. Simple.

In the corner, the knight has few escape squares which makes it so easily trapped. Now let's see what happens when the knight is on the edge, but not the corner (Yellow Zone):

Still in hot soup

Although the knight has more escape squares, White's king is ideally placed to keep watch over c4 and c6. After 1. Rb1! the remaining escape points b3 and b7 are cut off, and the knight is trapped and won with 2 Rb5.

What if we shifted the king to d4 instead of d5? Then 1. Rb1 no longer works because Black's knight can run away with 1... Nc6. You can see that bringing the knight out of the corner makes it more difficult to trap, since the knight will have more avenues of flight.

Another way for the defender to save himself is to protect the knight with his king. In our previous position, the Black king was a mere spectator in the game; now, let us see what happens when the king is there to help:

A saving grace for the knight


1. Kc5

Hoping for 2. Ra1 pinning the knight. 1. Rb1 Nb7 and Black's knight escapes.

1... Nb7+!

Not 1... Ka7? 2. Ra1 pinning the knight and winning it after Ka6 3. Ra2

2. Kc6

Again trying for 3. Ra1+ Na5 4. Ra2 winning the knight.

2... Na5+!
3. Kc7 Nc4
4. Rb1 Na5
5. Ra1 Kb5
1/2-1/2

Now both king and knight can make their way to the centre of the board. Draw.

...

With more escape squares and the protection of the king, the knight cannot be trapped easily by the rook. Thus, it is no surprise that a knight in the centre (Green Zone) is nigh impossible to trap:

Catch me if you can

I guess the position needs no explanation. You are free to work it out yourself if you are not convinced (:

As you can see, the concept of a pure rook vs knight endgame is very simple. So long as the defender keeps his knight away from the corner and side of the board, and protects the knight with his king, he should be able to secure the draw with correct play. It is all about whether the knight can be trapped/forked.

 ...

Now that we know the basics of pure rook vs minor piece endgames, what better way to finish off with... another challenge?

Position 1: White to move and win

Position 2: Black to move and win

I will let you think about the positions over the weekend. Have fun! (:

Links:




Sources:
https://www.cartoonstock.com/directory/c/chess_rook.asp
"21 Days to SuperCharge your Chess - Endgame Package" by Yury Markushin

Wednesday, November 18, 2015

Basic Rook vs Minor Piece Endgames: Part 1

And you thought I was finished with rook endgames! Like I once said, the breadth of rook endgame positions is so vast that many of us are far from mastering them.

Since we have managed to cover most of the basics of rook-pawn endgames (see database), I shall extend the discussion to basic rook vs minor piece positions. For today, we will be looking at a pure rook vs bishop endgame.

Let the showdown begin (Image from Dreamstime)

Many players, when encountered with this endgame, simply assume it is a draw and forget about it. They are right that it is usually a draw; but when faced with strong opposition, chances are they botch the defense and end up losing the game.

There is a simple rule to this. To defend successfully, the side with the bishop must stick his king in the opposite-coloured corner of the bishop.

Sounds weird? I will save on wordy explanation by throwing in a counter-example: When the defender has his king in the corner with the same coloured square as his bishop:

Position 1: White to move and win

Here, Black's bishop is dark-squared, and his king has been chased to a dark-squared corner (similar colour to the bishop). Now White can use a checkmate threat to win the bishop:

1. Rf1

Buying time for White to bring his rook into a suitable mating position. The immediate 1. Rc4? allows Black to escape with Kf8

1... Bh2

Or 1... Bd4 2. Rd1 Bb6 3. Rb1 Bc7 4. Rc1 Bd8 5. Rc8 winning with the same concept as the main line.

2. Rf2 Bg1
3. Rg2

Now Black's bishop is no longer safe on g2 and h2.

3... Bd4
4. Rd2!

A skewer: White is eyeing the d8 square where he can deliver mate.

4... Bb6

Black tries to defend.

5. Rb2 Bc7
6. Rc2

Now Black can no longer protect the light-coloured square c8.

6... Bd6

Or 6... Bd8 7. Rc8 winning.

7. Rc8+ Bf8

Blocking the check, but White simply plays a deadly waiting move:

8. Ra8!

The bishop is pinned, and Black is forced to step away.

8... Kh8
9. Rxf8#
1-0

...

So far so good... we know how the attacker can get a win by combining a mating threat with a pin. But that doesn't answer the question of why the defender can draw if he brings his king to the opposite-coloured corner?

What better explanation than another example:

Position 2: Either side to move draws

Now the defender has stuck his king in the right coloured corner. As usual White tries to chase out the bishop and employ his checkmate threat:

1. Rc2 Be5
2. Re2

Same old skewer, aiming for checkmate on e8.

2... Bf4!

Black keeps his bishop on the h2-b8 diagonal. You will see why.

3. Re8+

Of course 3. Re7 Bg3 4. Rf7 Be5 makes no progress.

3... Bb8
4. Kc6

The only way to continue if White wants to win.Now White cannot play the waiting move 4. Rf8?? because it'll be stalemate. Here, the Black king has no free square to go to. Take note of the difference between this and our previous example!


4... Ka7
5. Re7+ Ka8
1/2-1/2

But Black simply tucks his king back onto a8 and it's back to square one.

...

So here we have, a basic summary of how to play a pure rook vs bishop endgame:

  • As the defender, the safest way to draw will be to bring your king and bishop over to the corner with opposite-coloured square to the bishop. There, you can put your bishop on the correct diagonal to interpose any rook checks safely. The stalemate threat will save you.
  • As the attacker, your winning chances lie in luring the opponent's king to the same coloured corner square as the bishop, where you can use a checkmate threat to pin the bishop and win it.

In Part 2, we will move on to Rook vs Knight endgames.

Sources:
http://www.dreamstime.com/royalty-free-stock-photo-rook-bishop-chessboard-image27059045
"21 Days to Supercharge your Chess - Endgame Package" by Yury Markushin

Thursday, November 12, 2015

Dancing with the King's Indian

Barely 3 months after Queenstown I am back at the chessboard again. With 6 out of 9 points I was more or less satisfied with my results. Nevertheless, it is still my draws and losses that I am more interested in analyzing, to find out what went wrong.

Here's one of my games from Day 1 of the tournament, featuring a classic (and botched) attack in the King's Indian:

Checkerboard 5 vs Opponent
Thomson Chess Fiesta Challengers 2015 Round 4

1. c4 Nf6
2. Nc3 g6
3. d4 Bg7
4. e4 d6
5. Nf3 O-O
6. Be2 Nc6
7. O-O e5
8. d5 Ne7 (D)

Position after 8... Ne7

In the King's Indian Defence Black allows White to build a pawn centre before trying to undermine it with breaks like ... f5 and ... c6. White will use his extra space and attack on the Queenside, while Black concentrates on the Kingside.

9. b4 Nd7
10. Nd2 f5
11. Nb3 Nf6

Or 11... fxe4 12. Nxe4 blockading the centre.

12. f3 c6
13. Bg5

White could also try 13. c5 cxd5 14. exd5 e4 (14... dxc5? 15. d6 creating a powerful passed pawn.) 15. Bg5 exf3 16. Bxf3 with a very nice position and plenty of space in the centre.

13... cxd5 (D)

Position after 13... cxd5

14. Bxf6

The bishop wasn't doing much on c1, while the f6 knight is an important defender.

14... Rxf6
15. Nxd5 Nxd5
16. Qxd5+

When playing with a pawn chain, one of the attacker's plans is to replace any traded central pawns with his pieces, thus extending his grasp on the centre (see Part 3 of my article on pawn chains)

16... Kh8
17. Rad1 (D)

Position after 17. Rad1

Moving away from the black dark-squared bishop's line of fire and reinforcing the centre. The threat of 18. c5 is now in the air.

17... Qc7
18. c5 dxc5
19. Nxc5?!

Better was 19. bxc5 Be6 20. Qd6 with the threat of creating a passed pawn after the exchange.

19... Rb8
20. Bc4 Rf8 (D)

Position after 20... Rf8

21. Ne6?

21. Qd6! Qxd6 22. Rxd6 with a dominating position.

21... Qb6+!

I totally missed this saving move. I had been hoping for 21... Bxe6 22. Qxe6 followed by 23... Re7.

22. Qc5 Qxc5+
23. bxc5 Bxe6
24. Bxe6 (D)
1/2-1/2

Position after 24. Bxe6

Now the position is more defendable for Black. All he has to do is trade rooks and simplify to an opposite-colour bishop endgame.

...

What can we learn from this game?

  1. When playing with a pawn chain, your goal is to use your spatial advantage to launch an attack.
  2. When the pawn chain falls, the attacker can replace the pawns with pieces to further reinforce his central advantage.
  3. Likewise, the defender should attack the pawn chain and try to advance his own pawns should the chain fall.
  4. When attacking, try to bring in as many pieces as possible to maximize your firepower.
  5. Calculate carefully in complex positions!