Japanese noodles could be considered the "original fast food." Fast-cooking and quickly consumed, they are a dietary staple for the restless, hurrying population that packs the jammed streets of Japanese cities where accepted etiquette requires slurping noodles noisily in order to cool them off and indicate enjoyment.

While Italy, Germany, Hungary, China and many other countries highlight noodles in their cuisines, the noodle dishes of Japan are unique. They reflect the culinary philosophy of the country's cooks, who revere the pristine flavors of individual ingredients, and the dietary consciousness of a people who have always believed in the importance of impeccably fresh, healthful foods.

Soba, somen and udon, the most popular types of noodles, are eaten hot or cold. People in Tokyo and northern Japan prefer the strong flavor of the buckwheat noodle, soba, while in Osaka and southern Japan, wheat noodles (somen and udon) are traditional. Soba may be flavored with green tea (cha-soba), and somen may be enriched with egg yolks (tomago somen). Instant ramen noodles, so popular in Japan that they have come to be associated with that country by Americans, who also like them, are actually Chinese, not Japanese.

Noodle restaurants range from tiny street stalls to homey noodle shops to nationwide chains. Even in the smallest of them, care is taken to make the surroundings attractive and inviting.

At an unnamed but immaculate hole-in-the-wall soba-ya restaurant in Kyoto, I was treated to a bowl of the sticklike, thin, brown buckwheat noodles submerged in a fragrant steaming broth and garnished with vegetables and chicken. Nature pictures adorned the cheap wood-paneled walls, live flowers decked the simple tables flanked by wooden benches and in the minute restroom, where it was impossible to turn around without upsetting the philodendron resting on a shelf, the matching tissue holder and curtain were handmade.

Soba is also served cold, garnished with roasted seaweed (nori) and with a dipping sauce or in cold broth. In "Japanese Cooking: A Simple Art," Shizuo Tsuji, the renowned Japanese cooking teacher, recounts the old variety theater raconteur's favorite anecdote about a dying man in 17th-century Edo (now Tokyo) who had been subject to the then sophisticated notion that cold soba must be eaten without broth to be appreciated. The poor fellow's last wish was to eat just one bowl of cold soba swimming in broth before he passed away.

The Japanese also serve udon, ribbonlike wheat noodles, in bowls of hot fish bouillon. Topped with tempura, bean curd, mushrooms, bamboo shoots and egg, it is called nabeyaki udon. A special version, nagashi somen, which means floating somen, is worth seeking out. The chef passes carefully rinsed cooked noodles into a bamboo chute and clear flowing water carries them to the diner, who snatches the noodles up with chopsticks and coats them with a dip concocted of scallions, grated ginger, soy sauce and the hot green horseradish called wasabi.

For a treat of nagashi somen served in a pretty garden setting, it is worth a trip to Chaya Kado, a noodle shop in Kamakura, just one hour by train from Tokyo. The 65 remarkable Buddhist temples and 19 Shinto shrines, most of them erected during the Kamakura Period (1185 to 1336) when this city was the country's capital, are usually passed up by travelers on their way to the gaudier sights of Nikko. Yet the Dai Butsu of Amida, a colossal bronze statue of Buddha, presides in the courtyard of the Kotkuin Temple, and one of the five great Zen temples of Kamakura, named Enkaku-ji, houses what is said to be a tooth of Buddha brought from China. A visit to the monuments of Kamakura, many of them designated "Important Cultural Properties," and a nagashi somen lunch make a memorable outing that satisfies soul and body.

Closer to home, it is possible to sample a few noodle dishes in Japanese restaurants or to cook them yourself. Frank Kuge, for 28 years the owner of Sakura Palace restaurant in Silver Spring, recalls his grandmother making noodles, pounding the dough with a round stick, stretching it and then cutting it up with a little knife. At his restaurant, though, he used dried udon and somen for the noodle dishes he serves.

Nara in Bethesda, Yosaku in Washington and Niwano Hana in Rockville feature covered earthenware casseroles of nabeyaki udon. This is also one of the three noodle dishes cooked at Tsukiji, a new restaurant in Rockville. The others are zaru soba, cold buckwheat noodles laid out on a bamboo rack in a lacquer box, and yakisoba, the Japanese interpretation of the Chinese stir-fried noodle dish called lo mein.

Washington-area Japanese and other oriental groceries stock a variety of dried and fresh Japanese noodles, not only soba, somen and udon but also the wheat noodles kishimen and hiyamugi as well as the bean-thread noodles the Japanese call harusame, and shirataki. The slippery shirataki, made from the devil's tongue plant (Amorphopalus rivieri), is a familiar ingredient in sukiyaki. Dried soba and somen must be cooked about seven minutes, fresh about four, while dried udon requires 20 minutes and fresh about 10.

Grocery stores also sell canned noodle broth and dashi (fish stock) powder, Japanese soy sauce and mirin (sweet rice wine) for making homemade broth and all the other ingredients for the various Japanese noodle dishes.

Food historians may dismiss the legend that Marco Polo returned from his trip to China with noodles, but nobody can deny that the pasta dishes of Italy receive strong competition from the menrui dishes of the Land of the Rising Sun. ZARU SOBA (Cold Noodles) (4 servings) 2 cups dashi 4 tablespoons soy sauce (preferably Japanese style) 2 tablespoons mirin (or 1 tablespoon sake and 1 tablespoon sugar) 1 teaspoon sugar 1 pound dried soba (buckwheat noodles) 1 sheet nori (seaweed) 2 scallions, finely chopped 4 tablespoons grated daikon (giant white radish) 3 tablespoons grated fresh ginger 2 tablespoons wasabi (dried green horseradish) mixed with enough water to form a ball

To make dipping sauce, combine dashi, soy sauce, mirin and sugar in a saucepan. Bring to a boil. Cool and chill. Boil noodles in a large pot of water (about 6 quarts) according to package directions or until tender. Begin testing after 5 minutes by removing a strand and biting into it. The noodle should be cooked through (no hard core) but still firm. Drain and rinse well under cold running water. Chill 1/2 hour. Divide among 4 bowls. Toast nori over direct heat until crisp, about 1 minute. Crumble or shred with a scissors. Sprinkle over noodles. Arrange scallions, daikon, ginger and wasabi on a serving plate. Divide dipping sauce among 4 bowls. To eat, each diner adds scallions, daikon, ginger and wasabi to taste to the dipping sauce and dips a few strands of noodles at a time into the sauce before eating. NABEYAKI UDON (Noodles in the Pot) (4 servings) 8 1/3 cups dashi or chicken broth 2 teaspoons salt 6 tablespoons soy sauce (preferably Japanese style) 2 tablespoons sugar 2 tablespoons mirin (substitute 1 tablespoon sake and 1 tablespoon sugar) 4 dried shiitake mushrooms 1 pound dried udon noodles 4 medium shrimp, cleaned, shelled and deveined 4 eggs 4 scallions, chopped

In a dutch oven bring dashi to a boil. Reduce to a simmer and add salt, soy sauce, sugar and mirin. Soak mushrooms in boiling water to cover for 20 minutes. Discard stems and add caps to broth. Simmer 15 minutes. Boil noodles in a large pot of water (about 6 quarts) according to package directions or until tender. Begin testing after 10 minutes by removing a strand and biting into it. The noodle should be cooked through the center (no hard core) but still firm. Drain and rinse well under cold running water to remove surface starch.

To serve, divide noodles into 4 small casseroles. Arrange shrimp on top. Ladle 1 1/2 cups very hot broth into each casserole. Cover and bring to a boil. With the back of a spoon, make a small nest in the noodles, crack open an egg and drop raw egg into the nest. Cover and simmer until egg is cooked but yolk is soft. Sprinkle with scallions and serve.Adapted from "Japanese Cooking: A Simple Art" by Shizuo Tsuji YAKI SOBA (Spicy stir-fried noodles) (4 servings) 2 pounds precooked fresh yaki soba noodles (thin yellow noodles for stir-frying) 1/2 pound lean pork butt sliced into extra fine julienne strips 2 to 3 tablespoons oil 1 cup coarsely shredded cabbage or mixed cabbage and onions 2 teaspoons sake Pinch of salt 4 to 5 tablespoons wooster sosu (Japanese worcestershire sauce) 1 teaspoon ao nori (green seaweed flakes) 1 teaspoon chopped red pickled ginger

Rinse noodles in boiling water and drain. In a wok or large skillet saute' pork in 1-2 tablespoons oil over high heat, stirring frequently. When no longer pink, add cabbage mixture and stir-fry 1-2 minutes or until vegetables have softened a bit. Season with sake and salt and toss well. Add remaining oil and reduce heat slightly. Toss in the noodles and stir-fry 1-2 minutes. Season with wooster sosu and cook 1 minute. Serve hot, garnished with seaweed flakes and pickled ginger.

Adapted from "At Home With Japanese Cooking" by Elizabeth Andoh