Sure enough, Mr. Gorbachev and Mr. Ryzhkov appeared in view first and their colleagues held back, apparently following carefully planned stage directions. But is Mr. Ryzhkov second in power? Probably not, according to most Kremlinologists.

The key question today was who would follow Mr. Ryzhkov up the steps - Yegor K. Ligachev, whose status as the No. 2 party leader has been in doubt in recent months, or Lev N. Zaikov, whose star has been rising lately. The answer was Mr. Ligachev. On the Right, on the Left

Was the answer definitive? Yes, and no.

As third in line, Mr. Ligachev certainly retained his protocol position as the third ranking member of the leadership.

But when the leaders arrayed themselves on the tomb to watch the parade, Mr. Zaikov, the former head of the Leningrad party organization, stood immediately to Mr. Gorbachev's right while Mr. Ligachev was two places to the Soviet leader's left, with Mr. Ryzhkov between them.

Or is the spot occupied by Mr. Ligachev the place where the party's No. 2 leader should stand?

''When they get up there it gets harder to tell,'' the top Kremlinologist said. ''That's why you've got to look at the order in which they appear.''

''Once they've lined up, you have to move from left to right, back and forth, starting from Gorbachev and Ryzhkov's left, to get the ranking -assuming we're correct,'' he added.

By that calculation, seemingly confirmed by last year's anniversary appearance, Mr. Ryzhkov would stand to Mr. Gorbachev's left, with the spot to the Prime Minister's left belonging to the No. 2 party official. Last year and this year Mr. Ligachev held that coveted spot.