After 19...Nxc5 Black abandons the d4-square, and White would be slightly better.

There was nothing wrong capturing with the rook, but this is even stronger. With the knight coming to c4 White has to be slightly more careful.

Black is suffering some pressure on the queenside and Karpov finds a plan to immobilize his opponent!

The best move! Black was intending to play a6! For instance after 19.Kf1?! Black can play 19...a6! 20.Rxb6 20.Rb3 b5 and Black has managed to equalize. Rxb6 Bxb6.

This is the key. The pawn on b2 was hanging after the trade of rooks!

The idea is rather simple, to play Rba4 and Bxb6!, winning a pawn.

Black has played very passively, and now Karpov simply improves his position choking his opponent.

This is how the game finished. Clinical technique from Karpov.