The most technical. The king moves to a safe zone, and Black will inevitably come under an attack.
Unity Chess Club
Leonid Stein Lubomir Kavalek Caracas 1970 White to move
All of Black’s hopes of freeing his position are bound up with the advance d6-d5. White’s next few moves are directed at preventing this:
Black’s queenside is defenceless, with his light-squared bishop presenting an especially poor impression.
31...Nf4 32.Rdc1 Rg6 33.Bd1 Qd7 34.Bg4 Qe7 35.Nf5 Qg5 36.Bxf4 Qxf4 37.Qxb7 1-0
Unity Chess Club
Samuel Reshevsky Tigran Petrosian Zurich 1953 Black to move
Black’s position looks critical, as he lacks space and his pieces are uncoordinated. White threatens the break e5-e6, and also wants to play Bg4-f3, with the threat of d4-d5. But there is a brilliant way to change the contours of the game:
This is playing on the wrong flank, but even after 26.Bxe6 Qxe6 (weaker, by analogy with the game, is 26...fxe6, because of, say 27.Rf1 Ne7 28.Rg3, with the intention of including the h-pawn in the attack) 27.Rg3 Ne7 28.h4 Nd5, Black obtains positional compensation for the exchange, although not fully adequate.
26...Ne7 27.Bxe6 fxe6 28.Qf1 Nd5 29.Rf3 Bd3 30.Rxd3 cxd3 31.Qxd3 b4 32.cxb4 axb4 33.a5 Ra8 34.Ra1 Qc6 35.Bc1 Qc7 36.a6 Qb6 37.Bd2 b3 38.Qc4 h6 39.h3 b2 40.Rb1 Kh8 41.Be1
Even in the case where, after the exchange of the b2- and a6-pawns, White does not lose the d4-pawn, Black’s positional compensation will be sufficient, so a draw was agreed.