Cherry trees bloom in Tokyo by mid-April each year, but only 200 kilometers to the west, in the heart of the Japan Alps, there is still heavy snow. The great range of mountains, blinding white in the sun, marches across the horizon like a towering glacier advancing on the small town of Takayama in the valley below. By late afternoon, the narrow streets and old tile-roof houses of the village slip into cool shadow, while the setting sun washes the icy summits of the surrounding mountains in fiery gold.

Takayama is not at the top of most lists of recommended tourist destinations in Japan — it isn't as well known as Nikko, Kyoto, Kamakura — but it should be. It may display less of the gaudy spectacle and gilded grandeur of the better-known places. It is not within reach of any airlines or bullet trains. It does not attract vast weekend crowds. Indeed, Takayama is almost a cul de sac. Nevertheless, this isolated, 59,000-population mountain town is memorable for several reasons: its beautiful alpine setting, its untouched 18th-century antiquity, its colorful festivals in spring and fall, its happy, unhurried people.

There is something exclusive about Takayama, too. One does not go there simply because it seems "worth a detour" between one tourist destination and another — not at all. One should go as deliberately to Takayama as one would seek out a small, but exquisite, museum: because it is worth a visit in its own right.

Whole neighborhoods in Takayama are simply among the best preserved examples of "old Japan" that a traveler could hope to find in this relentlessly industrialized country. It is a place which the Japanese themselves call "little Kyoto," a town that is sometimes likened to our own Colonial Williamsburg for its historic authenticity.

"I've flown over Takayama hundreds of times," a Japan Air Lines pilot once told me, "and every time I look down from the air, I make a promise to go there for the festival some day. I haven't seen it yet — you are luckier than I!"

The trip from Tokyo requires nearly six hours by rail: first a two-hour bullet train ride southwest along the old Tokaido route to Nagoya; then a change to another railroad, the Chuo Line, which takes the traveler straight north into some of Japan's most rugged and dramatic mountain scenery. The train climbs between steep walls of heavily forested gorges and follows wild, rocky riverbeds which could be in Idaho or Switzerland. There are dams and hydroelectric stations and big timber. Massive piles of logs wait at sawmills and small furniture factories are surrounded with precise, weathered stacks of cut lumber.

Just before reaching Takayama, the train makes a long looping descent from the hills to a broad valley. A swift, shallow river runs sparkling blue over a stony bed. The Norikura Express No. 1, its wheels crying like iron violins on the curving track, follows the river into town.

The Miyagawa flows down from the mountains and runs through Takayama; in the shadows of its bridges, trout and red carp and sweetfish prowl the clear water. In April, they swim with their heads pointed upstream and their hungry mouths yawning open. In winter, when the river freezes, the fish sleep and heavy snows move down from the nearby Hida mountains and muffle the town. Then Takayama children get out the wooden sleds which their fathers still make for them. Some of Japan's best builders and craftsmen (Hida-no-takumi, "the skillful carpenters of Hida") come from this region. Woodcarving is an art most boys learn at an early age.

For a first-time visitor coming into town on the train, Takayama seems a place of manageable size: six kilometers from end to end with the river running down the middle. Four kilometers wide. All streets laid out in a grid formation. A flat town, sitting on a flat valley floor with the mountains all around.

A tourist information office is in front of the railroad station. With luck, someone there may speak English — but even if not, the pleasant young women who greet visitors understand what every tourist needs first: a map. After that, perhaps a hotel reservation — or a rental bike.

It is possible to walk across the contemporary downtown area in less than half an hour; a stroll along the length of the river would take a little longer. This new part of town resembles many other Japanese communities, but cleaner and slower paced. All of the principal tourist sights — temples, museums, old neighborhoods and markets — are also within easy walking distance of the river and might easily be covered in a day. But what a waste of make-believe that would be! Takayama is a town in which to let oneself slip back in time.

I had left Tokyo on the first bullet train, 6 a.m. It was noon when I arrived in Takayama. Even though I had been here before, I looked forward to a quiet afternoon of getting reacquainted before the annual spring festival — Sanno Matsuri — turned the town into a giant celebration. Takayama's two festivals, in April and October, are among the most colorful events of their kind in all Japan, not even excluding the more famous Gion festival in Kyoto.

But first the town. It was founded in 1583, in the age of the shoguns. A castle was built and six warlords of the Kanamori clan ruled for 107 years, until replaced by the notorious Tokugawas who ruled from far-off Edo (Tokyo). The Kanamori mansion still stands on the west side of the river. It was converted to an administrative office — a sort of feudal town hall — by the first Tokugawa shogun in the 17th Century. Today, tourists stroll stocking-footed through its tatami-matted rooms and old offices; they may also visit the rice granary next door.

Takayama has the usual quota of temples and shrines for a Japanese town of its age and size. The oldest of these, Kokubunji, dates from the 8th Century (rebuilt several times after fires). There is a 1,000-year-old ginkgo tree near the pagoda. Takayama also has two museums in which some of the elaborate festival paraphernalia, the floats and lion-dance masks, are permanently displayed for the benefit of those tourists who must miss the big events. There is also a general museum, a folk-art gallery, a toy museum (many antique dolls in western dress); an archaeology museum — all small but meticulously maintained.

The real essence of Takayama, however, the one attraction which, for me, sets it apart from any other travel experience in Japan, is a compact district of old, perfectly preserved (not restored or replicated) merchants' mansions. Three pedestrian streets in this area are lined solid on both sides with these original 200-year-old houses. No modern structures intrude, no utility poles or wires, no parked motorcycles, nothing to break the spell. These short, parallel furui-machinami (old fashioned streets) are reason enough in themselves for a visit to Takayama.

The lattice-screened house fronts in this area are made of uniformly dark, unpainted woods — in keeping with the mandate of the Tokugawa government: no decoration, no display of the homeowner's wealth on exteriors. The houses are one- and two-story structures, built flush to the street; there are no sidewalks.

In a single morning or afternoon of sightseeing in this neighborhood, a visitor will gladly remove shoes and pay small admission charges several times in order to explore some of the finest old Japanese houses preserved anywhere.

Many of these old mansions are still the residences (and warehouses) of tradesmen, among them a candle merchant with an interesting lantern collection, and several sake distillers — who hang great sculpted balls of cedar leaves (sugitama) over their front door when new sake is for sale. Sake in Takayama, invariably served in traditional square wooden cups, is reputed to be as good as the best in Japan: clean mountain air plus pure alpine water produces a superior product, the locals say.

Three old houses in particular have been opened to the public as living examples of earlier ages. The interior of the Kusakabes' century-old residence and store, for one, exhibits a lofty, two-story foyer (for summer cooling) with visible open beams. These heavy, foot-square timbers are as perfectly fitted as cabinet work, a tribute to the skill of the Hida-region builders. This spacious house, registered as an Important Cultural Property, is furnished with antiques and also serves as a folkcraft museum.

For over three centuries, one of Takayama's daily spectacles of color has been a flower and vegetable market which stretches out each morning along one bank of the river. Farmers' wives start setting up their stalls shortly after sunrise. Depending on the season, their handcarts and bamboo baskets overflow with crisp, washed greens, golden chrysanthemums, polished eggplants, yellow-white cabbage, spring flowers, several types of nuts and mushrooms.

The housewives of Takayama move along the row of stalls, wearing white aprons over their kimonos, their hair drawn back in sleek, black buns, their arms accumulating neatly-tied packages as they go. There are no price tags, no sales pitches, no haggling. Buyers and sellers alike seem to know their roles from centuries of practice and tradition. They greet each other like old friends.

If there is one thing for which Takayama is famous, even among Japanese who have never been there, it is matsuri — the festivals! These are held spring and fall in honor of planting and harvest, and they turn normally sedate old Takayama into a happy madhouse.

The centerpiece of both festivals is a group of 23 primitive but richly decorated parade floats, some of which are 500 years old. Tall as houses, these creaking, high-wheeled vehicles were originally built and maintained as a show of wealth and power by some of the leading merchants of the town. Later, they became the responsibility of various neighborhoods. They are richly lacquered and gilded with many fancy wood carvings by old-time Hida craftsmen.

During the two days of a festival, each float is attended and accompanied at all times by a crew of costumed figures representing some period of Takayama's history. On the night of the first day of festival, the floats are illuminated with hundreds of swaying, bobbing paper lanterns and are manhandled and rope-hauled through the narrowest byways of the town to the accompaniment of wailing flutes, thundering drums and much happy laughter.

To be in the streets with the people of Takayama at festival time is not to be a tourist at all, but somehow to feel a part of Japan itself.