Most nights, Moscow's Estrada Theater is alive and kicking with song-and-dance troupes. For the past two months, though, sellout crowds have packed the old hall to watch two men sit for hours at a table, each exquisitely immobile except for an occasional flick of the wrist. A whole line of swiveling chorines could not have elicited more excitement than those flicks, for the event was the world championship of chess, the No. 1 sport and all-round mania of the Soviet Union.
The defending champion was wily Tigran Petrosian, the former street cleaner who swept through the ranks of top chess...