Anatoly Karpov and Victor Korchnoi adjourned the fifth game of their world chess championship match after 45 moves yesterday in Merano, Italy. Korchnoi had a slight but probably not a winning advantage over the defending champion. Karpov, who needs six wins to keep his championship, leads the match by a score of 3-0 with one draw.

Korchnoi played more like his old self after resting through the weekend at Merano, an Alpine resort town. Game 5, scheduled for Saturday, had been postponed to Monday at his request. The opening, familiar from games 1 and 3, rapidly branched off in new directions, with sharp tactical play on both sides and many early exchanges. The style of the game was more Korchnoi's than Karpov's, but the usually cautious and relatively colorless champion held his own in the tactical fireworks. By move 20, more than half the pieces were off the board, including the queens. In the adjourned position, Korchnoi enjoys a one-pawn advantage, but Karpov seems to have excellent blockading chances.

The moves of the game follow:

Korchnoi, white; Karpov, black. 1. c4, e6; 2. Nc3, d5; 3. d4, Be7; 4. Nf3, Nf6; 5. Bg5, h6; 6. Bh4, O-O; 7. Rc1, b6; 8. cxd5, Nxd5; 9. Nxd5, exd5; 10. Bxe7, Qxe7; 11. g3, Ba6; 12. e3, c5; 13. dxc5, bxc5; 14. Bxa6, Nxa6; 15. Qxd5, Nb4; 16. Qc4, Qf6; 17. Nh4, Qxb2; 18. 0-0, Qxa2; 19. Qxa2, Nxa2; 20. Rxc5, Rfc8; 21. Ra5, Nc1; 22. Nf5, Rc7; 23. Nd4, Rb8; 24. Ra1, Nd3; 25. Rfd1, Ne5; 26. Ra2, g6; 27. Rda1, R8b7; 28. h3, h5; 29. Kg2, Kg7; 30. Ra5, Nc6; 31. Nxc6, Rxc6; 32. Rxa7, Rxa7; 33. Rxa7, Rc2; 34. e4, Rc3; 35. Ra2, Kf6; 36. f3, Rb3; 37. Kf2, Rc3; 38. Ke2, Rb3; 39. Ra6ch, Ke7; 40. Ra5, Kf6; 41. Rd5, Ra3; 42. Rd6ch, Kg7; 43. h4, Rb3; 44. Rd3, Rb5; 45. Ke3, adjourned.