Whether it's Tokyo or Kyoto or points in between, food is an obsession in Japan.

There are sushi bars, soba stands, yakitori bars, French pastry shops, tofu specialists and shabu-shabu joints. There are tonkatsu-ya, the restaurants specializing in deep-fried pork cutlets; tamago shops for sweetened omelets; and unagi-ya, freshwater eel restaurants.

Vending machines offer 10 kinds of tea, hot and cold.

Some places are for eating on the run — like the noisy ramen stands where patrons stand and slurp. Others are perfectly quiet and spiritual, like the kaiseki restaurants where Japan's best chefs practice their art.

"It stimulates the creative process," says chef Lee Hefter of Spago Beverly Hills, who travels to Japan often for inspiration. "I let it digest for a month and then go back to my notes and get inspired again."

Hefter plots his trips with precision. He gets tips from other chefs. He talks with chefs in Japan. He checks a Japanese food Web site, www.bento.com.

"It's a lot of work," he says. "And then you can't always get into the restaurant."

On this trip, Hefter, who also owns Cut steakhouse in Beverly Hills with Wolfgang Puck, starts with Kobe beef, one of the hundreds of types of artisanal beef in Japan. There are 41 prefectures that raise Wagyu cattle and produce their own tender, marbled, meticulously graded beef that winds up in restaurants such as Aragawa, where one steak can cost $1,400.

On an earlier trip, Hefter found the inspiration for the combination of ultra-high temperature and wood smoke he uses to cook the steaks at Cut.

Tonight, Hefter wants to check out yakiniku — the Japanese version of Korean barbecue. The restaurant, Shotai-en, is relatively inexpensive. The tab will come to about $30 a person. And Hefter has ordered a lot.

Almost instantly, the beef starts coming to the table. Hefter takes charge, dabbing slivers of raw beef with chile paste and onion, and passing them around.

"You only live once!" says Hefter.

Just one velvety bite is cool and subtle.

Hefter turns to the tartare.

"OK if I do the mixing?"

He breaks an egg yolk and works it into the meat. He scoops a spoonful onto each sheet of nori, slips in a shiso leaf and folds it into a cone.

There is the crunch of the nori against the creamy shock of the meat. It is gone in two bites.

A waiter pulls down a copper chimney from the ceiling, and another waiter brings a cast-iron grill pot piled with glowing charcoal.

"I'll tell you, I'm not doing the cooking," Hefter says, but he reaches for the vegetables.

He puts the onions on the grill, then shishito peppers, carrots, mushrooms and leeks — the long Tokyo negi that are left whole and grilled. Next come the shrimp, other meats and — the star of the show — a platter of Wagyu: three kinds of beef, each more marbled than the last.

BUSY TSUKIJI MARKET

After dinner, it's 11:30 p.m., and the Ginza is a blazing postcard, quiet except for a few circling taxis and a cluster or two of wanderers. The next day, Hefter heads for Tsu-kiji Market, the world's largest fish market — 2,000 tons of fish move through here six days a week. It's the best place to understand why a Japanese sushi restaurant is a travel destination.

If it swims, it's here — turtles, eels, clams, spiny lobsters, shrimp, silvery needlefish, crabs, abalone, firefly squid with googly eyes, octopus and stalls filled with uni, sea urchin roe which looks like slices of ripe apricot.

And, of course, tuna.

Tsukiji's tuna auction draws fishermen from around the world. At dawn, the auction is in full swing. As one row of enormous tunas, steam rising from their icy skins, is sold, another is moved in. Motorized flatbeds bring ever more fish. This is where the city's sushi chefs shop.

NO CRAZY SUSHI ROLLS

On this trip, Hefter will eat sushi once: at Sushidokoro Shimizu, an eight-seat sushi bar that has Tokyo buzzing.

Shimizu is in a narrow alley, amid apartment doorways and houseplants set out in the rain. Eight stools, a smooth pale counter, and behind it, the formidable chef Kunihiro Shimizu.

Shimizu is preparing wasabi paste. He rules his space without a word. An assistant brings out the rice, a gorgeous rosy color.

Shimizu starts preparing giant squid, scoring and cross-hatching the flesh. There is no long list of fish to choose from; Shimizu serves only seafood in season. As much attention is paid to the rice as to the fish; it is seasoned with a dose of kasuzu vinegar, and the grains are so flavorful that different varieties are used to complement different fish. There are no crazy sushi rolls; actually, there are no rolls at all.

Shimizu presents the squid, then maguro, the lean tuna belly, and chu-toro, the fattier belly. There's kohada, a spring specialty, the lightly picked Japanese shad, salted and marinated in vinegar, and needlefish that looks like a sparkling silver chain.

Shimizu continues, picking up hamaguri, a reddish braised clam, and salmon roe so fresh it's like eating sea foam.

At the end of the meal, Shimizu poses for pictures with Hefter.

A MASTER AT TEMPURA

Cooking vegetables requires the hand of an artist. Hefter knows the man: Fumio Kondo, tempura chef extraordinaire.

"It's amazing how many people go through life thinking they've had tempura," Hefter says.

Kondo, the chef's eponymous tempura bar in the Ginza, has only a dozen seats. Kondo whisks the tempura batter, quickly dipping fish or vegetables into it, and dropping them into hot oil. He lays the tempura on sheets of paper on trays.

Prawns, succulent and sweet, the crust perfect and fragile; fat pieces of asparagus; half-moons of lotus root; kisu, a small, delicate white fish; taranome, a mountain vegetable that looks like celery and has a barely bitter taste.

"You can tell the guy's a master at what he does. He really attacks it like an art," says Hefter. The batter is thin, "just a coating to protect it while it's frying. He lets the ingredients shine through."

Hefter asks if baby eels are available. Kondo smiles and, ah, here they are: each a tad wider than a strand of spaghetti, bundled with a shiso leaf and fried. Hefter's in heaven.

'IT'S A DYING ART'

Kaiseki is the haute cuisine of Japan, the ultimate expression of reverence for ingredients, respect for nature and the seasons, the skill of the chef and the art of dining.

The meal takes place in a hushed tatami room, traditionally with one table. Each course has its own visual language, not only in the artistic arrangement of the food, but also in the plates chosen to hold it.

The framework is formal: 14 courses that include two artfully composed appetizers, a sashimi course, a simmered dish, a grilled dish, a steamed course, a middle course that comes in a lidded dish.

Kaiseki chefs cook only what is in season, and the "seasons" change every two weeks. At the end of March, they are cooking young bamboo, harvested the moment it sprouts; cherry salmon caught off the coast of the Sea of Japan; the slightly bitter sprigs called mountain vegetables; and, of course, cherry blossoms and leaves.

Kaiseki is what Hefter wants to eat.

"It's a dying art," he says, of the cuisine born in Kyoto.

THE CHEF'S FAVORITE

Down a flight of stairs on a Ginza side street is Uchiyama, Hefter's current favorite.

There's a tatami room, but Hefter prefers to eat at the counter. Here, you can see the chef at work. Lunch begins with a cube of sesame tofu, its powdery white skin concealing a creamy, warm center; a dish of eggplant, firefly squid, sea urchin and miso, and sashimi presented with sprigs of shiso.

Hefter tears the tiny purple flowers from the branch and they drift over the fish, evocative of the drifting cherry blossoms outside.

Savory mochi comes wrapped in a cherry leaf in a bowl of thick dashi broth with bamboo and a cherry blossom. The leaf tastes intensely of cherry — the wood, the fruit, the leaf in this single bite. Buried inside the mochi is a creamy sea urchin.

"This kind of cooking," says Hefter, "a lot of foreigners never see."