Katsuo Dashi is a traditional Japanese soup stock made from bonito flakes. To make this dashi, you will need the following ingredients: bonito flakes, kombu seaweed, and water. First, wipe the kombu seaweed with a damp cloth to remove any dirt. Then, place the kombu in a pot with water and let it soak for about 30 minutes. After soaking, heat the pot over medium heat and bring the water to a simmer. Just before the water comes to a boil, remove the kombu from the pot. Add the bonito flakes to the pot and simmer for about 5 minutes. Then, strain the dashi through a fine-mesh sieve to remove any solids. Katsuo Dashi is a versatile soup stock that can be used as a base for various Japanese dishes, such as miso soup, noodle soups, and hot pots.