Harusame, commonly known as Japanese glass noodles, are thin, translucent noodles that become almost thread-like when cooked. Their name literally means “spring rain,” an apt description of their delicate appearance. Although believed to have originated in China, harusame is said to have been introduced to Japan during the Kamakura period (1185–1333), alongside fucha ryori, a style of vegetarian Buddhist cuisine associated with Zen temples.
In China, glass noodles are traditionally made mainly from mung bean starch. In Japan, however, harusame is generally produced using starch extracted from sweet potatoes or potatoes.
The manufacturing process involves kneading starch with hot water to form a dough, then forcing it through small holes into boiling water to create noodle-like strands. The strands are subsequently frozen, thawed, and dried. This freezing method gives Japanese harusame its distinctive texture. Small hollow spaces can remain inside the noodles, allowing them to absorb flavors particularly well during cooking.
Harusame is used in a wide variety of dishes, including soups, hot pots, stir-fries, and salads. Because the noodles readily absorb sauces and broth, they complement ingredients such as meat, seafood, and vegetables.
Preparation time is important, as the noodles need different soaking or rehydration times depending on the recipe. When boiled, they expand to approximately three times their original size. When deep-fried, they can swell to around ten times their original size, becoming light and crisp—a texture often used in garnishes and other dishes.
Nara Prefecture is one of Japan’s principal production areas for harusame. The cities of Sakurai and Gose together account for approximately 60 percent of the country’s total production, making the region particularly important to Japan’s glass noodle industry.
For travelers exploring the historic Asuka and Kashihara area, harusame offers a glimpse into the region’s food manufacturing traditions. Its simple appearance, delicate texture, and ability to absorb rich flavors have made it a versatile ingredient in Japanese cooking.