In Japan, they classify supremely gifted artisans and artists as National Treasures. With the completion of the Modern Art Museum of Fort Worth, which opened yesterday, we may as well proclaim Japanese architect Tadao Ando to be a World Treasure.

That's how good the building is -- an inspiring work of art for works of art. The architecture is reason enough to make a pilgrimage to this midsize Texas city. And the fact that the new museum stands across the street from Louis I. Kahn's great Kimbell Art Museum will make architecture lovers everywhere put Fort Worth at the top of their travel wish lists.

Of course, the world already has crowned Ando. The 61-year-old self-taught architect received the Gold Medal of the American Institute of Architects a year ago, and before that he had been awarded the Pritzker Architecture Prize and practically every other serious architectural honor the world has to bestow.

But most of the awards were given before Ando had completed any major commissions outside Japan. During the 1970s, '80s and early '90s he peppered his native Kansai region with extraordinary buildings, small and large. They were modern buildings -- Ando had carefully studied the modernist masterpieces of the West, and his intention was (and is) to extend the modernist tradition. All the same, his work was (and is) indelibly Japanese in character. Many wondered how, or even whether, the Ando aesthetic of simple forms and Zenlike silences would survive in other cultures.

Now we know. Ando translates beautifully, thank you. We got a good sense of that last year with the unveiling of his building for the Pulitzer Foundation for the Arts, an austere gem that perfectly suits its happenstance, transitional neighborhood on the edge of downtown St. Louis.

However, the Pulitzer is a rather petite building designed for a single, strong-minded client. The Fort Worth Modern, by contrast, is a comparative Goliath overseen by an ambitious board of trustees, commissioned only after a high-profile international design competition, and located next to Kahn's masterpiece. It's the big test, and Ando passed with a very, very good grade.

I must admit, I had my doubts. Ando's drawings for the building had been widely publicized, and I hadn't been totally convinced by what I saw. The design for a series of big boxes seemed excessively simple, even for Ando. Publicity materials describing the building's "double skin" -- a concrete structure wrapped in glass -- were intriguing but not reassuring. You were left to worry, "Can he pull it off?"

Nor were first impressions of the actual building altogether encouraging. From the outside, the much-anticipated squaring-off with Kahn is an anticlimax. As it happens, the Modern obliquely faces the Kimbell's rear facade -- not an ugly facade but, still, a rear. The urban space between Ando's building and Kahn's is uncompelling, at best.

The Modern's long front facade is, indeed, that of a basic modernist box, albeit one with an emphatic cantilevered roof overhang and an elegant skin of metal and glass. It is beautiful in its way but not terribly enticing. Unlike Kahn's splendidly modulated front entrance, there is no mystery or ceremony in approaching the high, off-center entryway of the Ando building. You just go in.

And then, right away, you begin to experience the magic, generosity, subtlety and self-confidence of Ando's art. The long, rectangular entry hall is a spacious, high-ceilinged civic room, an elevating space.

At midlevel the room is traversed by a long, narrow pedestrian bridge with glass railings, a concise line that enlivens the space. At one longitudinal end are the entry to an auditorium and, off to the side, a path to the cafe. At the other end are a bookstore and, off to the side, a path to the main galleries. These oblique pathways are important -- they let you know that nothing in this building is quite as straightforward as it may seem.

Most important, the entry hall is a see-through room, with high walls of clear glass in the center of each of its long sides. Immediately upon entering, you feel your eyes being drawn across the space to the view directly opposite. There is sunlight, and water.

Establishing a direct, intimate and subtle relationship between inside and outside, architecture and nature, is a strong motif in Ando's work. But nature in an Ando design is not the untamed wilderness of the American imagination. Rather, it is as carefully conceived and constructed as a Zen garden (or as an Ando building) -- an ordered, contemplative space of self-discovery or revelation.

Water often plays a major role in these Ando mise-en-sce{grv}nes. At the Fort Worth Modern, unlike any other Ando design I can think of, the water is a placid pool of a somewhat irregular, "natural" shape, almost as if the Japanese architect were paying homage to the romantic landscape tradition of Frederick Law Olmsted. The effect, however, is far from Olmstedian. This is no pond in a picturesque glade. It's an essential, integral part of the architecture. The water sets off the building, and vice versa.

Access to the outside is unhindered. From a perch on the opposite side of the pool you get a clear understanding of the building's basic organization -- it consists of five parallel, two-story rectangular structures. The longest two of these form the museum's front, and house the entry hall, auditorium, classrooms and administrative offices. The three shorter pavilions, spectacularly reflected in the pool, are devoted almost entirely to galleries.

Anyone acquainted with Kahn's Kimbell Museum will immediately recognize the similarity, for that wonderful building also is laid out in parallel pavilions. Kahn was one of the masters the young Ando adopted as exemplars, and the influence runs deep.

It's hard to imagine Ando's Spartan geometries of reinforced concrete without Kahn's prior example.

Kahn died at age 73 in 1974, two years after the Kimbell was finished. In its layout and many other ways, the Fort Worth Modern is an act of profound respect from student to teacher, from one architectural generation to another. But though it is not inaccurate to refer to Ando as a student -- his lifework exemplifies an impassioned curiosity -- he is, of course, a master in his own right. Ando's Fort Worth Museum is replete with declarations of his own hard-earned independence.

Some of the contrasts are obvious. Ando's building is twice as large as Kahn's. Its spaces are more varied and, in many cases, more expansive. Its engagement of the outdoors is more persistent, even aggressive. Ando's two-story pavilions are post-and-beam affairs with flat ceilings, as opposed to Kahn's magnificent vaults. Ando, too, insisted upon bringing natural light from above into his galleries, but his system of skylights and concrete baffles is much more circumspect than Kahn's.

Other differences are more subtle. Ando, like Kahn, is an aficionado of reinforced concrete. But Kahn loved the stuff mainly for its plasticity and structural strength -- the rough textures and patterns of his Kimbell vaults have the verve of abstract expressionist paintings. Ando also utilizes the material's strength, but he's a perfectionist who adores its subtle colors and smooth surfaces -- his walls at the Modern are made with the finesse of sumi paintings.

Once you are inside the Fort Worth Modern, you are really inside -- like other Ando buildings, this one possesses an inner essence that is hard to describe and hard not to feel. It has to do with a sense of security and serenity the spaces induce -- Ando buildings almost always are conceived as contemplative retreats from the pressures and mediocrities of contemporary life. Architecture has a moral purpose, he believes, and above all this is, he says, "to create a space where people can live, think and create."

For all of its serenity, however, this building is spatially dynamic. Walking around in it -- and outside it, too -- is a real treat, for there are many surprises. You round a corner from the entry hall, for instance, and come unexpectedly upon a grand stairwell, ascending to a green self-portrait of Andy Warhol on a concrete wall. You round another corner and suddenly find yourself in a narrow chamber with water and sky on one side and art against concrete on the other -- the "double skin" idea works, you realize, and in the most enchanting way.

And it just goes on. Ando is perhaps one of the few architects who can transform fire stairwells into chambers of shadowy beauty. Or who would think of erecting a concrete wall outside a museum cafe that uncannily brings to mind the experience of looking through an opening in a traditional Japanese villa?

Many of the galleries are conventional, high-ceilinged rectangles -- and this is good, for art rarely needs architectural competition. But in certain places here, the art and the architecture coexist in beautiful tension -- Director Marla Price and chief curator Michael Auping found perfect Ando spaces for works by Warhol, Martin Puryear, Anselm Kiefer, Michelangelo Pistoletto and others.

Ando's spaces are uplifting, but very serious, even somber. They challenge both the visitor and the art.

After spending some time in this museum (and before that, in the Pulitzer Foundation), you realize why those concerns about Ando in translation proved to be unfounded.

Ando isn't entertaining you with little snippets of Japanese culture -- he's aiming right for the human heart, wherever it may be.

Ando believes that "architectural space creates consciousness, an awareness of a larger universal rhythm and balance." This statement is a measure of the man's audacity.

The new Fort Worth Modern is an embodiment of these lofty ambitions, and it's a worthy neighbor to Kahn.

Tadao Ando's Modern Art Museum of Fort Worth: Extending the West's modernist tradition while keeping a subtle Japanese character.A building in which nothing is quite as straightforward as it may seem: The front of the Fort Worth museum is sheathed in glass and a silvery metal.Ordered, contemplative settings full of spatial surprises: Michelangelo Pistoletto's "The Etruscan" enlivens a room. Art and the architecture co-existing in beautiful tension: Martin Puryear's 1996 "Ladder for Booker T. Washington."