Except for the cherry blossoms, Washington may not look very Japanese. But behind the city's marble exterior lies a veritable Kyoto-on-the-Potomac. You can eat sushi, fight with bamboo swords, play Go and sleep on the floor -- all without physically leaving Washington. There's even a tea house whose sliding doors open on a garden meant for contemplation.

Here's where to find things Japanese in Washington -- from Armor to Zen. ARMOR: Japan had knights in armor, too, only they were called samurai. A set of samurai armor given to President Teddy Roosevelt for his peacemaking role in the Russo-Japanese war is on display in the Asia hall at the Smithsonian's Museum of Natural History. In addition to the armor, there are traditional Japanese farm implements; folk toys such as samurai dolls, dragon boats and playing cards where you match up lines of poetry; and folk craft such as bamboo lunch boxes and wooden buckets. BONSAI: As the haiku distills a poem into 17 syullables, bonsai distills a whole landscape into an artificially dwarfed tree growing in a pot or tray. The National Bonsai Collection (open daily 10 to 2:30) at the National Aboretum, 24th and R Streets NE, holds some 50 such trees, some as old as 350 years. A bicentennial gift from Japan, the trees grow, bear cones and change with the seasons -- just like big trees. If you want to dwarf your own trees, the National Arboretum teaches bonsai for beginners. The next course starts April 21, and there's a $20 materials fee. Call 472-9279 to register. An exhibition by the Potomac Bonsai Association will take place at the Arboretum April 25 and 26. BONSEKI: Another very Japanese way to bring nature into your home is to paint a landscape in a tray with sand and stones. Kiyoko Uyede teaches this art, called bonseki, in her home in Annandale. Call 323-5020 for details. CRANES: The long-legged birds represent long life to the Japanese and, since the birds mate for life, they also symbolize true love. Cranes have long been a popular subject for Japanese artists, and a splendid example of crane-inspired art is a six-panel screen showing cranes and a stylized river at the Freer Gallery of Art. The Freer has the best collection of Japanese art in town: rooms filled with screens, fans, scrolls and ceramics. If you want to study Japanese art more formally, the Smithsonian Associates have a six-week course in 19th-century art beginning April 16.Call 357-3030. DIABUTSU: About this time of year, Japanese long to go on pilgrimages to religious shrines, such as that of the Great Budda, or Daibutsu, at Kamakura. The 92-ton bronze image is 35 feet high; a smaller version of the Buddha in the same sitting position and giving the same hand sign for steadfast faith sits in the garden at Anderson House, 2118 Massachusetts Avenue NW. You can make a pilgrimage to see this 5 1/2-foot-high Buddha between 1 and 4, any day except Monday. (admission free). EATING: Nouvelle cuisine owes its esthetic emphasis to the Japanese, who lavish attention on the presentation of food as well as on its preparation. Colors and textures are juxtaposed and, for added interest, the shape, color and texture of the dishes change with each course. To get the full treatment in a local restaurant, you have to arrange a "special dinner" a day or so ahead. A recent "special dinner" at the Mikado, 4707 Wisconsin Avenue NW, included seven esthetically and gastronomically pleasing courses. First came the hors d'oeuvres: A scooped-out orange shell filled with salmon caviar and chopped radish; beef with scallions; scallops and chicken livers. The chawan mushi, or steamed egg custard, contained clams and tiny woodland mushrooms called enoki. In the sashimi, or raw fish, course, the flounder was shaped into a rose and the squid was rolled around sea urchin roe. The bamboo and yam course was followed by asparagus tempura, served with horseradish on blue-and-white oblong plates.

The broiled lobster tails were served with shabu sauce (soy sauce, horseradish, green onions and sake). The claw meat, mixed with mushrooms and rice, was served in individual wooden vessels that looked something like lanterns. Dessert was well-limed papaya. The tab was $40 a person, not counting beer and sake.

If you want to create your own Japanese banquet, a good place to start is the Mikado Grocery next door to the restaurant. The store stocks everything from instant miso soup to a dozen kinds of seaweed to pickled plums to frozen gyoza, or dumplings. There is also octopus, salmon fresh enough for sashimi, and beef that the butcher will slice thin enough for sukiyaki. If you want to spruce up your sashimi presentation, the Mikado sells decorative green leaves -- made of plastic.

If you really want to eat Japanese style you have to sit on the floor, on a cushion called a zabuton. You can do this at the Sakura Palace, 7926 Georgia Avenue, Silver Spring -- if you call in advance and ask for a tatami room. Tatami are the floor mats used in Japanese homes, and the Sakura Palace recently added a whole new Japanese-style section, built by carpenters from Japan. Each alcove has a tokonoma, or beauty alcove, the esthetic focal point of a Japanese living room, which usually holds a scroll and a flower arrangement. The only concession to Western weaknesses is that under the low Japanese table there's a pit where you can dangle your legs if you don't want to fold them decorously under your kimono. FUTON: Traditionally, Japanese also sleep on the floor, on mattresses falled futons. But according to Dan Yoshida, owner of the Ginza, a Japanese shop at 1721 Connecticut Avenue NW, most of the people who buy the shop's futons are non-Japanese dwellers in efficiency apartments who want to increse their living space. Japanese bedding -- consisting of a folding mattress topped by a thick cotton-stuffed quilt -- can be tucked away in a closet each morning, and the whole outfit costs about $200. In addition to futons, the shop stocks antique iron tea kettles, tansu chests, lacquered rice-serving dishes, Fukugawa porcelain, kimonos and the special underwear everyone except geisha girls wears underneath, books on Japan and such folk art as tanukis, mischievous pot-bellied badgers who carry sake jugs. GARDENS: To the Japanese, gardens are scenic compositions of rocks, plants and running water -- preferably with an island in it and a bridge over it. The Japanese garden at Hillwood, the estate of the late Marjorie Merriweather Post at 4155 Linnean Avenue NW, has two redwood bridges that arch over a mini-stream and connect a small island to the rest of the garden. The gardens and the house are open for tours by reservation; call 686-5807.

If you're planning your own Japanese garden, you'll need a stone lantern, with which Japanese have traditionally lit the path to tea ceremonies. The 17th-century carved granite lantern that stands among the cherry blossoms in West Potomac Park may serve as your model, but unless you're very rich you'll probably have to settle for a lantern of cast stone. Reinhard Pohlen, owner of the Old World Gift Shop at 9150 Baltimore Boulevard (U.S. 1) in College Park, mixes sand, cement and ground stone and pours the mixture into molds. His Japanese statues sell from $20 to $150. GO: Aficionados consider Go the ultimate board game, more difficult -- and more spiritually rewarding -- than chess, and the shoguns always retained Go players in their entourages. The Greater Washington Go Club plays the game Friday evenings at 8 at the Cedar Lane Unitarian Church, 9601 Cedar Lane, Bethesda, and welcomes participants and observers. A book on Go for beginners is available at the meetings. HONDA: A form of Japanese locomotion, popular in this country, that may become extinct if the Reagan administration has its way. HOUSES: The traditional Japanese house is one story, with a thatched, tile or shingle roof, and lots of sliding doors opening on gardens. It's constructed of natural materials that are allowed to retain their rustic appearance. Westerners -- and modern Japanese -- have adapted traditional architecture to their own needs. A good example of a Japanese-influenced house stands at 3020 University Terrace NW, the former home of Sen. and Mrs. George McGovern. IKEBANA: Japanese don't just stick flowers in a vase. They use them to reconcile the leading principle (heaven) with the subordinate principle (earth) through the art of ikebana, or flower arranging. For an overview of the different styles -- or schools -- of ikebana, trot out to the Mazza Gallerie from April 13 to 18 for a show by Ikebana International, a worldwide group incorporating all styles of Japanese flower arranging. To get your own hand in, sign up for a course in the Ikenobo school of ikebana held Thursdays at 1 at the Shogun Gallery, 1083 Wisconsin Avenue NW. To register call 965-5454. JAPAN-AMERICA SOCIETY: The Japan-America Society of Washington is a group for people with a serious interest in things Japanese. The group has a library and holds meetings with speakers and films. On June 6, the Japan-America Society, in conjunction with the Japanese-American Citizens League, will hold its annual bazaar at Mount Vernon, will hold its annual bazaar at Mount Vernon College. There will be demonstrations of Japanese arts such as ikebana and raku pottery, and lots of Japanese food. For information about the society or the bazaar call 223-1772. KOI: Fancy carp called koi adorn Japanese garden pools. Seven varieties of koi, a gift of the Japanese to President Nixon in 1973, swim in a Japanese-style pool at the beleaguered National Aquarium in the basement of the Commerce Department. KOTO: This long, zither-like instrument is the sine qua non of Japanese classical music. The Washington Toho Koto Society, which also includes shamisen and shakuhachi players, will perform next at the Northern Virginia Folk Festival at the Thomas Jefferson Community Center in Arlington May 9. Kyoko Okamoto, the dpyenne of area koto artists, gives lessons in the instrument. Call her at 434-4487. LANGUAGE CLASSES: The U.S. Japan Culture Center, 2139 Wisconsin Avenue, NW, teaches Japanese at all levels. Call 6760. MARTIAL ARTS: When samurai weren't fighting, they played the kinds of sports that kept them in fighting shape. One such sport, called kendo, involves fencing with a bamboo sword you hold with two hands. When you score a hit on a valid part of your opponent's body, you have to call the point in Japanese. Washington Kendo Club meets Saturday mornings at 11 at Slayton House in Columbia. The club gives eight-week introductory kendo classes. For details, call Kurt Schmucker, 301/721-0902.

Karate came to Japan from Korea, but the Japanese have their own style, with more emphasis on character-building and blows with the upper body. The Washington D.C. Karate Club practices a Japanese school of karate called Shotokan. Trainings are held Tuesday, Thursday and Friday evenings from 7:30 to 9 at the Jellef Boys Club, 3265 S Street NW. MASHIKO: "Mashiko is a town where everybody make pottery. When you approach the town, you smell the smoke from all the kilns," said Marjorie Hemmendinger, owner of Full Circle, an Alexandria gallery that imports this folkcraft earthenware. The gallery, at 317 Cameron Street, also handles the works of Teruo Hara, a well-known Japanese potter who lives in Warrenton.

In addition to pottery, Full Circle sells hand-stenciled and hand-dyed paper, some of it by Keisuke Serizawa, who is one of Japan's "living treasures." There are also stenciled zabuton covers, antique silk also stenciled zabuton covers, antique silk kimonos, folk toys and cloth carp kites -- the king Japanese with sons hang on their houses on Boy's Day, May 5. NOREN: These colorful cotton curtains are placed at the entrances of shops and restaurants in Japan to keep out wind, cold, heat and dust. Americans find they make good room-dividers -- especially between a dining room and a kitchen. Full Circle and the Ginza, both have good selections of noren, from about $7. O-MAMORI: Japanese put an "o" in front of words for things they revere, such as tea or a hot bath or mamori -- talismans on sale outside religious temples. Sharon Burton and Linda Beeman came to Washington from the San Francisco Bay area and brought the work of many Japanese-inspired California artisans with them.

There are Crest and Crane evening bags with Japanese heraldic insignias and family crests; quilted Japanese-style jackets appliqued with irises; silkscreened pelican vests and fish aprons -- all created by Japan-influenced Americans. From Japan itself come kimonos, fireman's jackets and, especially for cherry-blossom time, cherrybark boxes. Cherry blossoms were the symbol of the samurai, and when they weren't making war or practicing martial arts, samurai carved things out of cherry-tree bark. PAGODAS: These houses of worship with their multiple tile roofs that curl upward at the edges came to Japan and Buddhism, in the sixth century. In American, the style is used for a whimsical touch on secular buildings: See the pagoda-style red-tile roof and cupola on the Victorian house at 3154 Highland Place NW. A more extreme example is the pagoda built as a sorority house at the National Park Seminary at Forest Glen. Now part of the annex to the Walter Reed Army Medical Center, the pagoda houses an army captain and his family. QUOTABLE: Impress your friends by quoting a Japanese proverb. For example, "Never trust a woman even if she has borne you seven children"; "To lose is to win"; "Dumplings rather than blossoms." RYONAJI: The garden at the Ryonaji Temple in Kyoto is considered the finest of its type. In line with the temple's Zen philosophy, the garden contains only the bare essentials: 15 rocks of varying sizes arranged on a flat piece of ground covered with white sand. If you can't make Kyoto, the Japanese embassy here has a similarly austere garden, made up entirely of stones and fine gravel imported from Japan. Although some people read images of bleak islands in a vast seas into the garden, it's meant not to evoke particular scenes but to induce meditation. The garden surrounds a ceremonial tea house copied from a 17th century structure and shipped to Washington unassembled. The tea house has two rooms -- the koma, where the tea ceremony takes place, and the hiroma, where the tea is served. Tours of the garden and tea house are given Thursdays, by appointment. Call 234-2266. SHOJI: Inside Japanese houses, shoji -- screens of Japanese rice paper in wooden frames -- separate one room from another Oriental Living, 4923 Bethesda Avenue, Bethesda, custom-makes shoji doors to fit American homes and usually substitutes fibergolass for the rice paper. SUSHI: These seaweed-vinegared-rice-and-raw-fish sandwiches are traditionally served at tiny bars in Japan. Washington has its own such place, the Samurai Sachiko at 2309 Wisconsin Avenue NW. As you clean your hands with the traditional steaming towel that is brought to you in a bamboo basket, you can watch an artist roll up the sushi and arrange them in a lacquered bowl. If you can't stay, the restaurant will pack up a lunch box of sushi for you. Japanese frequently bring such boxes on picnics and train trips.

Other sushi bars include the Fuji, at 3299 M Street NW, and the Sakura Palace at 7926 Georgia Avenue, Silver Spring. At the Sakura, you can somethimes watch videotapes of sumo wrestling from Japan.

If you want to make your own sushi, the Mikado Grocery sells the ingredients plus the flexible bamboo sheet that helps roll the ingredients into a neat package. SUISEKI: Only the Japanese could raise stone-viewing to an art and give it a name, suiseki. The administration building at the National Arboretum, 24th and R Streets NE, holds six stones given this country by Japan. The stones have names -- such as Noble Boat Mountain Stream Stone and Quiet Mountain Stone -- that suggest the spiritual response they are meant to invoke. TEMPURA: Most area Japanese restaurants serve this dish of lightly battered, deep-fried shrimp, mushrooms and eggplant (the Japanese also use chrysanthemum leaves). But the Japan Inn at 1715 Wisconsin Avenue NW has a special tempura bar where a lunch of soup, rice, tempura and tea costs $5.75. UENO PARK: This is where Tokyo-ites flock to view the cherry blossoms. The stone lantern in Ueno Park is the twin of the one in Potomac Park, where Washingtonians flock to view the cherry blossoms. The cherry blossoms around the Tidal Basin have clones in suburban Kenwood. Cuttings of these gift Yoshino cherry trees were grafted onto native wild cherry trees and the results line the streets of Kenwood, which is reached by following Wisconsin Avenue to River Road and turning right on Dorset Avenue. VIEWS: Japanese like to rank or at least enumerate vistas. Every picturesque place has at least eight "must see" views, so you know exactly where to stand to watch the moon rise over Lake Biwa, for example. Mount Fuji, being special, has a hundred views, all of which were painted by the artist Hokusai in a picture book called The Hundred Views of Mount Fuji. Hokusai and Fuji are represented on an alley wall at 3510 P Street NW. An artist who signed the work "J.McConnell" copied Hokusai's stylized waves overwhelming a crew of boatmen rowing with eyes cast up at snow-covered Fuji. WOODBLOCK PRINTS: These prints are really the creation of three people -- the artist who draws a picture and pastes it down on a specially prepared block of cherry wood, a cutter who follows the artists' lines with a chisel, and a printer who inks the block and pulls the prints. Japanese woodblock printing began in the 17th century, and its first subjects were denizens of the "floating world" of courtesans and kabuki actors.

Toni Liberthson, co-owner of the Shogun Gallery at 1083 Wisconsin Avenue NW, which specializes in Japanese woodblock prints, has been collecting the prints since she was given one in 1967.

"It's an addictive art," say Liberthson, whose gallery is a treasure trove of three centuries of Japanese prints. Upcoming shows include prints by Toyokuni III (April 11 through May 31) and Noh Play prints by Kogyo (June 5 through July 31). Also see a show of the work of Kawase Hasui this Saturday and Sunday from 10 to 6 at The Hendricks Art Collection, 9101 Old Georgetown Road, Bethesda.

One of Japan's greatest living woodblock artists, Umichi Hiratsuka, lives in Washington but exports most of his work to Japan. The Mikado Restaurant has a good collection of Hiratsuka's works on its walls. X-RATED: The Geisha House Paradise at 2009 K Street NW offers 25-cent "adult" movies. No subtitles are needed. YAKITORI: These skewers of chicken, marinated in soy sauce and sugar and grilled on a hibachi, are sold by vendors in Japan. To make your own, thread pieces of boneless chicken breast on wooden skewers that have been soaked in water. Mix equal parts of soy sauce and sake, add a pinch of sugar and some minced ginger and garlic. Brush the chicken with the marinade and grill. ZEN: This is the contemplative sect of Japanese Buddhism, which seeks salvation through "divine emptiness." The Ka Shin Zendo, the Washington Zen center at 1717 P Street NW, holds frequent meditations and welcomes neophytes on beginners' night, Wednesdays from 6:30 to 9. Participants are asked to wear "quiet-colored comfortable clothes." For details call 234-4102. a