As soon as Gary Kasparov moved his king's pawn to start the second game of the World Chess Championship, the kibitzers thought something was up. They had been expecting an opening on the queenside. Clearly this called for instant analysis. So, as the players quickly proceeded with the Flohr-Zaitsev Variation, the kibitzers next door at the Hotel Macklowe sought out Eric Schiller, an American player. Mr. Schiller had not only just published a treatise on that variation, he had also recently spent a week at Mr. Kasparov's training camp on Martha's Vineyard.

''They figured I must have known this was coming,'' Mr. Schiller said after the game Wednesday night. ''Of course I had no idea what Kasparov was going to do or why he chose that opening. But I just smiled knowingly and muttered about how I wasn't at liberty to discuss what had gone on at training camp, and people assumed I must really be in the know.''

This is one of the beauties of chess: It can take very little to sound like an expert. A beginning player can be a master kibitzer -and kibitzing, of course, is what the world championship is all about. The match inside the Hudson Theater, where the third game is scheduled today, is friendly compared to the struggles among the analysts outside.

Championship chess kibitzing can be practiced anywhere by anyone with the critical faculties of a television sports commentator. Anyone capable of offering insights like ''Defense is the name of the game'' and ''He definitely came to play today'' can learn to sound like a grandmaster by following a few principles of the experts:

Be careful with your opening. Too many novice kibitzers give themselves away in their first sentence by pronouncing the champion's name ''KAS-pa-rov.'' The accent should be on the second syllable. But even better, in some experts' minds, is the authoritatively familiar ''Gary.''