Kombu tsuyu is a type of Japanese soup base or dipping sauce that is made from kombu (dried kelp), bonito flakes (dried fish), soy sauce, mirin (sweet rice wine), and sugar. It has a deep, umami flavor and a slightly sweet taste that is perfect for enhancing the natural flavors of vegetables, noodles, and meats. Kombu tsuyu is typically used as a base for hot pot dishes, udon and soba noodle soups, and as a dipping sauce for tempura and other fried foods. It is also a popular condiment for rice dishes and can be used as a seasoning for marinades and sauces. Kombu tsuyu is widely available in Japanese grocery stores and can also be purchased online. It is a versatile and flavorful ingredient that is a must-have for any home cook interested in Japanese cuisine.