TOKYO, June 12— It took Vladimir Horowitz 79 years to get to Japan, which by his reckoning was not all that long, no matter what some Japanese might think.

For two decades, music people in Japan had been urging him to come, but he kept putting them off. Not that he was uninterested, he said, but the thought of having to fly so many hours, frankly, scared him.

Now here he was Saturday night, bowing slightly and waving his handkerchief to an audience that rose in ovation after a two-hour recital that he gave in NHK Hall, Tokyo's efficient performing-arts center.

He had been warned not to expect too much enthusiasm: Japanese audiences tend to be decorous. Not this time, though. For 14 minutes, most of the 3,500 ticket holders stood and cheered, then cheered some more, bringing him back on stage nine times before letting him amble off into the clear night. The Virtuoso Looked Pleased

Mr. Horowitz could not have looked more pleased with his Tokyo debut. ''You see,'' he had been saying before the performance, ''you have to try something for the first time.''

It was only his second appearance outside the United States in 31 years -he played in London a year ago - and the Japanese gave his arrival the four-star treatment of a certifiable big event.

Both Saturday's recital and another scheduled for Thursday night were sold out in no time. Some people had lined up for two days, standing outdoors in a heavy rain part of the time.

Well-known pianists such as Hiroko Nakamura spoke rhapsodically about the visit. One pianist, Kazuko Yasukawa, said she did not want to attend the Tokyo recitals only out of fear of disturbing the ''strong impression'' created when she heard Mr. Horowitz play in Paris in 1937.

When he landed June 2, some 150 photographers were waiting for him at the airport. Since then, newspapers and magazines have elbowed one another to chronicle his comings and goings - an assignment which, truth be known, has not been formidable. Mr. Horowitz has hardly left his $1,200-a-night hotel suite. 'I Have Work to Do'

''I cannot lose too much time - I have work to do,'' he explained. ''I wanted to see so many things. I wanted to see the underground system. It's fantastic, I hear. But it's a luxury for me.''

Adjusting to the 16-hour time difference from California, his last stop, was no problem. As usual, Mr. Horowitz sleeps late, in a darkened room. Days have been consumed with practicing, watching movies in his suite and taking afternoon walks with his wife, Wanda - always in the company of a severe-looking bodyguard trained in the martial arts.

This first encounter between Japan and the Russian-born virtuoso required compromises from both. After years of insisting on 4 P.M. performances, Mr. Horowitz has lately favored an 8:30 P.M. starting time. Normally, Tokyo concerts begin at 6:30 or 7. Mr. Horowitz agreed to 8 o'clock.

For its part, the glacial Japanese bureaucracy found it could move fast when necessary. Agreed to Come 5 Weeks Ago

The pianist had agreed to come here only five weeks ago. Usually, the state-owned NHK Hall is booked a year in advance. That required a quick shuffling of schedules, including air time for a taped broadcast of the first recital tonight on the public television network - right after a popular samurai program.

All this reflects not only the strong grip that Western classical music retains but also a certain Japanese weakness for big names and labels, whether in musicians or designer clothes.

''Japanese audiences are funny,'' said a pianist, Shuku Iwasaki. '' 'I've heard Horowitz' - that is something to be able to say for your whole life. Whether you liked his playing or not is something else.''

There seems little doubt that many Japanese do indeed like Mr. Horowitz's playing. His records sell well. But some churlishness has accompanied this debut, with more than one critic saying that Japan was getting a less-than-top-notch Horowitz, a performer who, to their mind, is in technical decline.

A chorus of grumbling also rose over the ticket prices - a $210 top and a fairly substantial $34 for the cheapest seats. Costly Personal Needs

The unhappiness stemmed in part ofrom the costliness of Mr. Horowitz's personal needs.

For instance, a kitchen had to be built in his suite because he insists that all his meals - fish or chicken only - be taken there. The electrical wiring ran afoul of Tokyo fire laws, requiring new wallpaper and a special floor.

Several critics suggested in a music journal that the money might have been better spent to help victims of a recent earthquake in northern Japan.

''You should grumble at the management, not me,'' the pianist replied when told of these remarks. ''I didn't even know the prices until I got here.''

In the often worrisome fashion of the Japanese press, there was speculation that he might cancel at the last minute. The fear was unwarranted, and any complaints heard earlier in the week disappeared as soon as Mr. Horowitz sat down at his piano. Same Program as New York

He played the same program that had earned only mixed reviews in New York last month: Beethoven's Sonata in A major (Op. 101), followed by Schumann's ''Carnaval.'' After the intermission came a collection of Chopin - the Polonaise-Fantaisie (Op. 61), three etudes and, finally, a zesty Polonaise in A flat major (Op. 53).

The audience, an amalgam of the well heeled and the unheeled, was eager for more. But no matter how many times it brought Mr. Horowitz back for bows, he declined to give an encore. He had promised there would be none, and he kept his word.

''You see,'' he said, ''I have a very substantial program, and after a substantial program, you can't play a substantial encore. You play a little ... '' at this, he strummed the air with his fingers, tinkling an imaginary piano.

''It is,'' he said, ''anticlimactic.''

Illustrations: photo of Vladimir Horowitz