An amateur looking at this position will recognize the basic elements: White is attacking on the Kingside, Black on the queenside. There are potentially weak White pawns at f3 and d5 and Black ones at e7 and h7. White would love to occupy the holes at c6 and e6. Black is looking forward to the endgame where his two bishops and outside passed pawn ....h5! Will be trumps.

There is a lot more to notice here. But the master notices quite a bit more than the amateur does. The master recognizes an idea for White, the attack on h7, and begins calculating variations. He sees quickly that 1.Rh2 and 2.Rdh1 is one method, but it involves the sacrifice 1...Qxd5 and a black capture on d4, with unclear results. He also sees another method of exploiting that idea, and quickly calculates the basic winning line: 1.Rxh7!! The master knows what the winning combination feels like.

1.Rxh7 Kxh7 2.Rh1+ Kg7 Or 2... Kg8 3.Qxg6 and 4.Bh6+ with mate to follow. 3.Rh6!

The master will have also worked out the various side variations, such as 3...Be8, 3...Kf8, and 3...Bf5!?, coming to a favorable conclusion after a few further moves of analysis.