Saturday, October 4, 2014

Rook-Pawn endgames: Three vs Two (Part 1)

As we have seen earlier with Two vs One scenarios, rook endgames with the pawns on one side of the board is usually a draw as long as the weaker side can keep his rook active, trade pawns, and simplify the position to a Philidor/Inverse Philidor. When we extrapolate to a Three vs Two, we can see that this should be a draw too so long as the defender plays accurately according to the guidelines in our earlier post (http://nushsblackknights.blogspot.sg/2014/09/rook-pawn-endgames-two-vs-one.html).

However, if the weaker side plays too passively then sometimes he might end up in a situation where he ends up getting "squeezed" by his opponent's pawns:

White to move wins


In this position White's pawns eat up most of the space and squeeze Black's king into a fatally cramped position; such a troubling position is often caused by passive play from the defender.

1. Kh5

White wants to trap Black's king on the edge of the board, where he will slowly be crushed by the weight of White's pawns and the threat of back-rank mate. 1. Kh5 prevents ... Kg6 after the White pawn advances to f6.

1... Rd8

The only defence against back-rank mate; 1... Rb7? 2. f6+ Kf8 3. Ra8+ leads to mate on the next move.

2. f6+ Kg8

2... Kf8 3. Kh6 (threatening the h-pawn) Kg8 leads to a similar position as the main line.

3. Kh6 Rb8

There is no better move; taking the rook off the back rank allows mate after Ra8.

4. Ra7

The threat is 5. e6 fxe6 6. Rxh7, where White's pawns should easily crush the Black king to death (just don't stalemate!).

4... Re8?

An attempt to stop White's threat. Unfortunately, it fails after:

5. e6!
1-0


5... Rxe6 6. Ra8 leads to mate, while 5... fxe6 6. f7 wins the rook.

...

The following is another example of how things can go bad for the weaker side if he gets squeezed:

Black to move wins

Here, it is obvious that Black enjoys a lot of space in the centre. How should he convert this advantage into a win? The plan lies in two parts:

  1. Get the king and rook out of the way, and reduce White's checking distance so as to avoid any annoying back-rank checks. Once the king has been evacuated from the c5 square, Black can proceed to push his pawn to c5 and create the "squeeze" we have seen in our previous example.
  2. Place the rook on the 7th rank and exploit the pin of White's c-pawn to his king by playing d4-d3.


1... Re3

It is important to occupy the e-file: In some lines where Black plays ... Kc3, he can defend from a check on the 6th rank by returning the Black rook to e3.

2. Rc8

After 2. Rb7 Re2 3. Kb1 Kc3 White is pushed into a fatal corner, while after 2. Rf8 Re2 3. Rf3 Kb5 4. Kb3 c4+ Black has also achieved the "squeeze" position as we have seen in our first example.

2... Re1!

This move forces White to play 3. Rc7/Rc6, reducing checking distance and spoiling any potential back-rank checks when the Black king moves off the c5 square.

3. Rc7

We have already seen that 3. Rg8 Re2 4. Rg3 Kb5 is bad for White, while 3. a3 (trying to exchange pawns, but Black already has too much space in the centre) 3... bxa3+ 4. Kxa3 Rb1 traps the White king, with the upcoming threat of ... Rb5 followed by ... Kc3

3... Re8!

Taking control of the last rank: Now White's rook cannot use the last rank to make any back-rank checks once the Black king has left c5!

4. Rc6

Once again 4. Rg7 fails to 4... Re2 5. Rg3 Kb5

4... Kb5
5. Rc7 Kb6

Preventing Rb7+ after ... c4

6. Rg7 c4

The "squeeze": Black's pawns have reached their ideal positions.

7. Rg6+

An attempt at long-distance checks, but now Black has a safe hiding square on a4. The other variations are:

7. Rd7 d3 8. cxd3 Re2+ 9. Kb1 c3 where Black's pawn is too far advanced, and winning is only a matter of technique and time-management.

7. a3 Re2 (7...bxa3+ also wins but not as quickly: 8. Kxa3 Re2 9. Rg6+ Kc5 10. Rg5+ Kd6 11. Rg4 Kd5 and Black should win the resulting two vs one endgame since his opponent's king is too far away) 8. axb4 d3! (exploiting the pin along the 7th rank) 9. Rg6+ Kb5 10. Ka3 Rxc2 11. Rg5+ Kc6 12. b5+ Kd6 and Black's pawn will queen first.

7... Kb5
8. Rg5+ Ka4 (D)
0-1

Looks familiar?

We have reached a similar position as that of the first example, which is an easy win. Now I will leave the rest of the game to you as a personal challenge: Find the fastest way to finish off White!

...

So it should be clear to us: There is no way the defender can allow such a terrible position to happen, which is why he has to keep his pieces and pawns as active as possible in such endgames.

Black to move


Here, Black must not allow White to push his pawn to f4, else it will create the dreaded "squeeze" position. With this in mind, the candidate move is not difficult to spot:

1... g5!

Locking White's pawn majority. Now, any pawn advance by White helps simplify the position into an easily drawn 2 vs 1 position.

2. Rd5

Hoping for a miracle after 2... Rxd5?? 3. exd5 Kf7 4. f4 where the outside passed pawn proves decisive for White. But Black is not so compliant as to trade rooks:

2... Rb3

Black simply follows the same guidelines as we have seen in our earlier article: Keep the rook as active as possible by tying down the enemy king to its pawns.

3. e5

Repeated checks with 3. Rd7+ Kg6 don't make any progress, while after 3. Kf2 Rb2+ 4. Ke3 Rb3+ White's king cannot hope to get closer to the rook without hanging his pawn.

3... fxe5
4. Rxe5 Kf6
5. Ra5 Kg6 (D)
1/2-1/2

A dead draw

With the Black king in front of the enemy pawns, any additional pawn trade will simplify the position into a draw Philidor/Inverse Philidor.

...

In the tussle among rooks and pawns, the goal of the stronger side is always to try and promote his extra pawn. To do this, there are two different tricks:

  • Entice the weaker side into trading rooks so as to create an outside passed pawn from the recapture, which we know by now is a valuable winning asset.
  • Advance the pawns to gain as much space as possible, so as to "squeeze" the opponent. When that happens, the combination of the pawns and the threat of back-rank mate should slowly crush the enemy king to death.

Not a pretty sight either (Image from Wiki)

As for the weaker side, one must make sure never to fall into the traps as stated above! To do this, we just needs the same set of guidelines (and I state "guidelines", not "rules"!) that I have provided in our earlier article:

  • Avoid trading rooks
  • Put the king in front of the enemy pawns
  • Keep the rook as active as possible (i.e. tying down the enemy king and pawns)
  • Seek pawn exchanges that help simplify the position
  • Additionally, use appropriately-timed pawn pushes to deny the stronger side any chance to grab space in the centre with his own pawns.

With that in mind, the defender should be able to avoid the terrible "squeeze" positions that we have seen earlier, and slowly simplify the position into a drawn Philidor/Inverse Philidor. Keep in mind: To defend well, active play is needed!

With that I stop here, and will proceed with a more complicated example in Part 2.

Links:
Two vs One: http://nushsblackknights.blogspot.com/2014/09/rook-pawn-endgames-two-vs-one.html

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

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