Sunday, December 07, 2014

The knight before

Ansell-Basman, London Chess Classic Super Rapidplay, round four.

I saw this position on Facebook this morning: Simon played the unfortunate 1. Rc5?? here and Basman went on to play Giri in the next round. I spent some time - rather longer than the forty seconds Simon had had available - trying to work out if 1. Rxe6+ would have done the job (there are of course other potentially strong moves) and after calculating several moves and concluding that I just didn't know, consulted the computer.

It turns out that the answer is clear and I had missed something early on.

So does 1. Rxe6+ win or draw? Why - and what do you think I missed?

[Thanks to Simon]


Adam FF said...

I'm seeing 1. Rxe6+ Rxe6 2. Nxe6 Ne4+ 3. Kf3 and if 3. ... Nxc3 4. b6 wins, whilst 3. ... Nd2+ 4. Ke2 (or 4. Ke3) doesn't seem to help Black either.

ejh said...

Indeed. What I wasn't seeing was 3. Kf3 - my mind just naturally pencilled in 3. Ke3, which doesn't seem to win. (3...Nxc3 4. b6 Nd5+, while other tries are for the readers, or their computers, to consider.)

Adam FF said...

I was playing 3. Ke3 initially too; it seems the natural instinct to avoid squares the same colour as the knight worked against us. You also need to visualise that the en pris knight on e6 prevents 3. ... Ng5+.

simona said...

I only considered Ke3 too, it's the natural square for the king away from knight checks.

I saw b6 was impossible after Re6 Re6 Ne6 Ne4 Ke3 Nc3, and wasn't sure if Nd4 (Nc7) instead was winning there, so I was about to play Re1 (from where the rook came) which should be winning too, but at the last second I thought "hang on, why not Rc5?" :)