Thursday, June 18, 2015

Practical Rook Endgames 06: Frontal and Long Side Defenses

I have thrown around the frontal and long side defense terms enough that it's appropriate to address them formally. Both of these defenses are for a lone rook to draw versus rook plus pawn when Philidor has gone awry.

For the frontal defense:

  • Attacking pawn has not yet reached its fifth rank
  • Defending king is cut off by the attacking rook on the long side of the board
  • Defending king is not cut off so much that the pawn can easily get to its fifth rank (Rule of Five may help here)
  • Defending king can quickly attack a rook on the second rank or one on the fifth rank (e.g. King is on 3rd or 4th rank)
  • Defending rook is in front of the pawn with checking distance (3 ranks between rook and pawn)

Frontal Defense: White can draw with either side to move

With White to move, probably safest is just to shuffle Kd4 and Kd3. Decreasing checking distance just a tiny bit with 1.Rf2?? will lose to Kg5! and the Black King will advance on the White Rook until it reaches f3 and escorts its pawn to f4, making a classic Lucena position. Failing to defend the fifth rank allows the rook to briefly defend the pawn laterally. 1.Kd2?? Kg5! 2.Rg1+ Kh4! 3.Rf1 Re5! 4.Kd3 {one step out of position} Kg3! 5.Ke4 Ra5! {spread offense} 6.Rg1+ Kf2 7.Rg5 Ra4+ 8.Kd3 Ra3+ and Black gets Lucena. If White goes too far north with Kd5, Black cuts off another file with Rd8+. With Black to move, if the king ventures out, White checks it while it protects the f-pawn; if the king is not protecting the f-pawn, White attacks the pawn. e.g. 1...Kg5 2.Rg1+! Kh4 3.Rf1! Kg4 4.Rg1+! Kh3 5.Rf1! Kg4 6.Rg1+=. The pawn must never be allowed to get any closer, else Lucena happens. If the Black Rook shuffles 1.Re7, the White King shuffles Kd4 or Kd3. If the Black Rook tries to get into the Spread Offense e.g. 1...Re5 2.Kd4 Ra5 Ke3 should lapse into a Philidor. In a previous post, I blogged about how this frontal defense resembles the Space Invaders video game.

For the long side defense:

  • Attacking pawn could be as far advanced as its seventh rank, so this defense works later than the frontal defense
  • Defending king is cut off by the attacking rook on the short side of the board
  • Defending rook has at least three clear files between it and the pawn (sufficient checking distance)

Long Side Defense: White can draw with Black to move

Black is in check, but he will find no shelter. If the Black King approaches the White Rook, the White Rook can get position behind the dangerous passer. e.g. 1...Kd1 2.Ra1+! Kc2 3.Ra2+! Kd3 3.Ra3+! Kc4 4.Re3 draws. The White King can take a stroll up to d7, but he will not find any respite from the checks. 1...Kd1 2.Ra1+! Kc2 3.Ra2+! Kd3 4.Ra3+! Kd4 5.Ra4+! Kd5 6.Ra5+! Kd6 7.Ra6+! Kd7 8.Ra7+! Kc8!? 9.Re7! draws. If White skewers the rook with 9.Ra8+ Kb7 10.Rxf8 e1=Q+ he loses. The Black King has to allow either White Rook to the e-file or get checked all the way back to d1.

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