"So many times have I heard my vegan and vegetarian friends complain about the fact that most dashi/soup stock is not done according to their priorities in Japan, making it impossible for them to enjoy food in this country.
Fortunately, this is a big misconception. Vegan dashi exists and is very easy to make or request.
Now, to make sure that the same friends can savor Japanese food, either at home or with friends, here is the basic and simple recipe!"
Pour water into a large saucepan. Drop konbu into the water. Bring to a simmer; the water will start sucking in the essence of the konbu. Add soy sauce, mirin, and sake. Simmer, tasting from time to time, about 5 minutes. Remove konbu and let cool completely. Pour into a bottle, seal, and store inside a refrigerator. Use as soon as possible.