Fails

It seems that I pick up The Manual of Chess Combinations, vol. 2 by Sergey Ivashchenko once every other week to work a page of exercises. A few days ago, half a page occupied part of my morning. I solved three successfully. This morning, the fourth one on the page did not present difficulty, but the last two did. I also managed to err in the sixth exercise on each of the the next two pages.

Exercise 144 struck me as a study in corresponding squares on first glance, but I gave too little attention to the simplicity of Black's ability to gain and maintain the opposition. Had I considered the possibility of a sacrificial breakthrough, I might have more quickly perceived the floating square idea. I spent some time teaching the floating square to a couple of students last week and should have seen it.

White to move

1.Kf2 (or any other king move) fails. 1...gxh4 2.gxh4 Kg6 3.Ke3 Kf5 4.Kf3 Ke5 and Black can shuffle the king back and forth.

Instead, 1.g4! wins 1...hxg4 2.h5 (also 2.d6). 

Before that one, I thought I had correctly solved number 143, but had also overlooked something simple.

White to move

I tried 1.Kg5, overlooking that I had nothing after 1...e6 2.Kf6 Ke8 3.Kg7 Ke7 and somehow I had hallucinated there being possible an outflanking maneuver. After 1.Kg7 Ke8 2.e6! fxe6 3.Kg8 Kd8 4.Kf8 Kd7 5.Kf7 Kd6 6.Ke8, White has successfully outflanked the Black king.

Number 150 was familiar and I instantly knew the correct answer, but could not perceive the reason the rook had to move to d2 instead of d1, so I tried Rd1 against Stockfush. Again, simple opposition gives Black a draw.

White to move

1.Rd2! wins 1...d4 2.Rd1! Kd5 3.Kd7 Ke4 4.Kc6 d3 5.Kc5 Ke3 6.Kc4 d2 7.Kc3 and the rook captures the pawn on the next move. After 1.Rd1 d4 2.Kd7 Kd5, White can try 3.Rd2 Kc4 4.Ke6 Kc3 5.Rd1 d3 6.Ke5 Kc2 and the rook must be given up for the pawn.

My error in number 156 stemmed from failing to recognize the possibility of Black achieving a Philidor position.

White to move

Black got a Philidor-type position after 1.Kc4 Rg8 2.Kc5 Rg1 3.dxe6 Rc1+.

White wins easily either with 1.dxe6 fxe6 2.Ra7 Rf8 3.Ra8+ Kd7 4.Rxf8 or with 1.Ra7 straight away.