Victor Korchnoi snatched a draw from a position that experts were calling lost in the 16th game of the world chess championship match in Merano, Italy. When the challenger sealed his 41st move Saturday, several grandmasters said Karpov would have an easy victory when the game was resumed yesterday. But Korchnoi's move, occupying an important white diagonal with his queen, offering a pawn sacrifice and threatening to check Karpov's king and activate a passed pawn, was enough to nullify the champion's hopes.

Korchnoi chose a psychologically interesting opening, identical to that of game 14, which he lost, but offering an effective new variation on move 14. The game was a seesaw battle all the way, but it ended with closely interlocked pawn structures and no clear winning line for either.

The hall went into a hubbub when Korchnoi's sealed move was opened. Analysts watching the game evidently had not expected the challenger to continue looking for possible winning threats when they thought his chances for a draw had faded. Karpov made one move in reply and agreed to a draw within five minutes.

Also surprised, perhaps, was Soviet Deputy Minister of Sport Viktor Ivanin, who had arrived in Merano with Karpov's wife, Irina, evidently for a victory celebration. Korchnoi's wife remains in the Soviet Union, denied an exit visa, and his son is in a prison camp there for refusing military service.

Karpov maintains a 5-2 lead, with six games needed to win. Game 17 is scheduled for tomorrow.

Moves of game 16:

White: Karpov; Black: Korchnoi, 1.e4, e5; 2. Nf3, Nc6; 3. Bb5, a6; 4. Ba4, Nf6; 5. 0-0, Nxe4; 6. d4, b5; 7. Bb3, d5; 8. dxe5, Be6; 9. Nbd2, Nc5; 10. c3, d4; 11. Bxe6, Nxe6; 12. cxd4, Ncxd4; 13. Ne4, Be7; 14. Be3, Nf5; 15. Qc2, 0-0; 16. Neg5, Bxg5; 17. Nxg5, g6; 18. Nxe6, fxe6; 19. Rae1, Qd5; 20. b3, Rac8; 21. Bc5, Rfd8; 22. h3, Qc6; 23. b4, Rd7; 24. Rd1, Rcd8; 25. Rxd7, Rxd7; 26. Re1, Qd5; 27. a4, Nh4; 28. f3, Nf5; 29. axb5, axb5; 30. Qe2, Qc6; 31. Rc1, Rd8; 32. Be3, Qd5; 33. Bf2, c6; 34. Qe1, Qb3; 35. Ra1, Qb2; 36. Rb1, Qa2; 37. Rd1, Rd5; 38. Rxd5, cxd5; 39. g4, Ng7; 40. Bc5, h6; 41. Qe3, Qc2 (sealed move); 42. Kf1, g5; draw agreed.