Challenger Gary Kasparov sealed his 42nd move yesterday in Game 19 of the world chess championship in Moscow, leaving champion Anatoly Karpov in what looked like a hopeless position. Then, in a triumphant, possibly contemptuous gesture, Kasparov showed the audience the sealed move, which he could have kept secret until the resumption of play today: a pawn capture with a check that drives the knife deeper into an already helpless victim.

It may go down in history as the move that won Kasparov the world chess championship. It is unlikely that Karpov will show up for the resumption of play today.

In the adjourned position, after Karpov takes his king out of check Kasparov could capture a knight, leaving no compensation. Alternatively, he could exchange a knight for a rook, a less powerful move but one that, with his pawn surplus, still should be enough for victory.

A victory in this game would make the score 10 1/2 to 8 1/2 in Kasparov's favor and raise the possibility that the match might not go to its limit of 24 games. Four more draws in the five remaining games will give Kasparov the title.

Karpov can tie the match and keep his title by winning two games, but with only five to play, that looks almost impossible. He has won two of the 19 games played so far, and they were two in a row (Games 4 and 5), but that does not look like a feat he can accomplish twice in one match, particularly at such an advanced stage.

Karpov's most obvious blunder may have been his 39th move, a pawn capture that subjected his rook to a pin and double attack, but his whole game looked like one long blunder. He moved both knights twice in the first nine moves, wasting precious time in the opening and putting his queen's knight hopelessly out of position until its final move, which made it subject to capture. He also dislocated his f-pawn on his fifth move for no perceptible advantage. These moves introduced a strange variation of the Nimzo-Indian Defense, with which Karpov has lost two previous games in the match. On the evidence of this game, the theoretical value of the new moves is zero. Karpov's level of play in this game did not look like that of a world champion.

White/Kasparov -- Black/Karpov

1. d4nf6 2. c4e6 3. Nc3Bb4 4. Nf3Ne4 5. Qc2f5 6. g3Nc6 7. Bg20-0 8. 0-0Bxc3 9. bxc3Na5 10. c5d6 11. c4b6 12. Bd2Nxd2 13. Nxd2d5 14. cxd5exd5 15. e3Be6 16. Qc3Rf7 17. Rfc1Rb8 18. Rab1Re7 19. a4Bf7 20. Bf1h6 21. Bd3Qd7 22. Qc2Be6 23. Bb5Qd8 24. Rd1g5 25. Nf3Rg7 26. Ne5f4 27. Bf1Qf6 28. Bg2Rd8 29. e4dxe4 30. Bxe4Re7 31. Qc3Kg7 32. Re1Bd5 33. Ng4Qf7 34. Bxd5Rxd5 35. Rxe7Qxe7 36. Re1Qd8 37. Ne5Qf6 38. cxb6Qxb6 39. gxf4Rxd4 40. Nf3Nb3 41. Rb1Qf6 42. (Qxc7(ch) sealed) Adjourned