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

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