Hippopotamus in the swamp during calculation
In a game against Vasiukov in a USSR Championship, Tal was calculating a knight sacrifice and found the variations too tangled to resolve. His mind drifted to a children's rhyme about dragging a hippopotamus out of a marsh, and he spent his thinking time mentally working out rescues with levers, ropes and a helicopter. He finally dismissed the hippo and played the sacrifice on intuition. The next day's commentary praised the move as the product of forty minutes of deep calculation.
