White has managed to isolate the enemy rook on b7.

With every exchange the inferiority of that rook will make itself more strongly felt.

Softening up the light squares.

In the event of 4...exf5 , one of several tempting replies is 5.Ne7+! Bxe7 6.Rxe7 , followed by Rdd7.

Prophylaxis against the ...b6-b5 advance, which from now on will be met by c4-c5.

Black has been deprived of any counterplay.

Desperation in a difficult position.

White went on to win.

Restricting White's intended queenside advance,which could have become real after 1...Bxa3?1 2.Nxa3 , followed by Nc2, a2-a3 and b3-b4.

Speeding up the kingside play before White consolidates with Nd2-f3.