game 1 Botvinnik vs Tal, 1961  (E48) Nimzo-Indian, 4.e3 O-O 5.Bd3 d5, 41 moves, 1-0 game 2 Tal vs Botvinnik, 1961  (B18) Caro-Kann, Classical, 45 moves, 1-0 game 3 Botvinnik vs Tal, 1961  (E48) Nimzo-Indian, 4.e3 O-O 5.Bd3 d5, 43 moves, 1-0 game 4 Tal vs Botvinnik, 1961  (B12) Caro-Kann Defense, 41 moves, 1/2-1/2 4 games