Most kombu comes from the cold waters off Hokkaido, the northern large islad of Japan. There are four representative varieties, depeding on the place where the kombu is harvested — ma-kombu from southwest of Hokkaido, hidaka kombu, from the central southern coast, rausu kombu, from the eastern waters, and rishiri kombu, from the north coast. The water temperature and the nutrient conditions in each location produce kombu of differing thickness, taste, aroma and texture. Processed dried kombu is covered with a white powdery dust. This is the source of its sweetness and good flavor, or umami. Too much or too little powder is the sign of bad quality. The appearance should resemble that of light frost on a leaf. Kombu is rich in minerals, vitamins, dietary fiber and iodine. Scientific studies also show that kelp contains chemicals that can fight high cholesterol and high blood pressure. Consuming Japanese stock everyday can help to ensure good health.

In the olden days, professional chefs and home cooks alike kept a block of processed, hardened katsuobushi in the kitchen. They shaved it using a tool like a carpenter's plane, producing just the right amount of shavings needed for immediate use. This method assured the maximum flavor, fragrance and nutritional value. Today, shaved flakes of katsuobushi are conveniently available in plastic bags. Katsuobushi is rich in minerals, vitamins, and protein. Freshly shaved flakes have a lighter, slight pinkish color and glossy appearance. As time goes by, the color changes to a less attractive brownish color. The flakes come in both large chip-like shapes and thinly sliced shavings. The latter type is generally used as a garnish.