“Japanese supermarkets are cathedrals of freshness,” says Naomi Moriyama, author of Japanese Women Don’t Get Old or Fat (Delacorte, $22, www.amazon.com). The traditions of Japanese cuisine are also rooted in fresh, healthy eating, which helps explain why Japan has an impressively low obesity rate. If you don’t have a Japanese market near you, try ordering from www.edenfoods.com/store or www.katagiri.com. Here, Moriyama’s essentials of Japanese cooking and how to enjoy them.

Daikon

Whether tossed into salads, simmered in soup, or grated on top of grilled fish as a garnish, this giant white radish adds a spicy punch and crisp texture to a variety of dishes. Its freshness can be easily tested by pushing the surface of the radish and making sure that the skin is tight and doesn’t feel rubbery. Moriyama prefers buying whole daikon with leaves, as it is usually moister than when purchased precut. Plus, she enjoys the mild, kalelike flavor the leaves can add to soup. Store daikon in the refrigerator in an airtight container and it will last up to a week.

Rice Vinegar

Distinctly mild and less acidic than western vinegar, rice vinegar is most commonly used in Japan for seasoning rice, soups, vegetables and salads. It comes in light (made from white rice) and dark (made from brown rice) varieties. Though Moriyama says the two are interchangeable for cooking, she prefers brown rice vinegar for its slightly milder taste. When shopping for rice vinegar, Moriyama advises staying away from brands that have additives, like sugar. “Look to see that it says '100 percent rice vinegar' on the label,” she says. Moriyama recommends refrigeration if you plan on keeping for several months.

Noodles

The two noodle varieties most often used in Japan are soba (made with buckwheat flour) and udon (made with white flour). Soba is marked by a nutty, earthy flavor, while udon tastes similar to everyday pasta. Both noodles are frequently used in soups or eaten, like pasta, as a casual main dish, either cold with a soy-based dipping sauce or hot with a meat, fish or vegetable topping. When shopping for soba noodles, look that they are made of 80 to 100 percent buckwheat (no more than 20 percent flour). “Beyond that, their flavor becomes too diluted,” Moriyama says. Although fresh noodles are often found in Japan, dried soba and udon are most commonly available in the United States. Dried udon and soba are stored just like dried pasta and have an equally long shelf life.

Miso

Miso is a fermented soybean paste that comes in several varieties, the most common being red miso, which has a stronger, saltier flavor, and white miso, which tends to be sweeter and lighter. “A lot of people mix the two, especially in soups,” Moriyama says. Miso also makes a terrific marinade for fish and meats, “just like a barbecue sauce,” Moriyama adds. When purchasing miso, Moriyama recommends looking carefully at the sodium count, as some brands can have an extremely high percentage. “I try to look for miso that has 500 to 600 milligrams of sodium; if it has more than 900, I stay away,” she says. Miso either comes in a tub or a plastic bag. Moriyama prefers the tub as it is easier to store and less messy. Keep miso in the refrigerator stored in an airtight container, and always look on the date on the package to see how long it will keep.

Nori

This dried sea vegetable, or seaweed, is a great source of protein, iron, calcium, minerals and iodine. Known for its subtle flavor, nori is often cut into square sheets and used to wrap sushi rolls or shredded and sprinkled as a condiment in soups or on noodles. Nori has a short shelf life, however, so Moriyama recommends using it soon after it is opened. Store nori in a dry place, in an airtight container or resealable plastic bag.