Victor Korchnoi sealed his 41st move in the 12th game of his world championship chess match yesterday in an inferior position but one that offered apparent chances of a draw with world champion Anatoly Karpov. The score remains 4 to 1 in Karpov's favor, with six points needed to win the match.

Karpov changed his match strategy by using a new opening -- the English opening, which has been Korchnoi's favorite with white. Korchnoi replied with a vigorous defense, but dropped a pawn to Karpov's impressive lineup of power on the queenside. In the adjourned position, Karpov's extra pawn is partly neutralized by the fact that the players have bishops of opposite colors, a situation that frequently ends in a draw.

The moves played so far in game 12 are given below.

Karpov: White; Korchnoi: Black: 1. c4, Nf6; 2. Nc3, d5; 3. cxd5, Nxd5; 4. Nf3, Nxc3; 5. bxc3, g6; 6. d4, c5; 7. e3, Bg7; 8. Bb5 ch, Nd7; 9. 0-0, 0-0; 10. a4, a6; 11. Bd3, b6; 12. Rb1, Bb7; 13. e4, Qc7; 14. Re1, e6; 15. e5, h6; 16. h4, Rfd8; 17. Bf4, Nf8; 18. Be3, Rab8; 19. Qe2, Bc6; 20. Bxa6, cxd4; 21. cxd4, Bxa4; 22. Nd2, Qc6; 23. Rec1, Qa8; 24. Bd3, Bc6; 25. f3, b5; 26. Nb3, Rbc8; 27. Nc5, Nd7; 28. Ne4, Bxe4; 29. Rxc8, Qxc8; 30. Bxe4, Qc4; 31. Bd3, Qc3; 32. Bxb5, Nb6; 33. Qd3, Nd5; 34. Bf2, h5; 35. Qxc3, Nxc3; 36. Rb3, Nd1; 37. Rd3, Nxf2; 38. Kxf2, Rb8; 39. Bc4, Rb2 ch; 40. Kg3, Rb4; 41. Rc3, and Korchnoi sealed his 41st move.