Seiro soba is a chilled soba (buckwheat noodle) dish served in a bamboo or wooden steamer basket called a "seiro." The noodles are boiled, rinsed in cold water, and placed in the basket. They are eaten by dipping into a cold soy-based sauce (tsuyu) mixed with condiments like scallions or wasabi. The dipping sauce is made from dashi stock using bonito flakes and kelp, giving it a rich umami flavor. Seiro soba is popular especially in summer and highlights the natural texture and aroma of soba. It is often served with tempura or duck dipping broth in soba restaurants across Japan.