1000 ml water.
10 grams dried kelp.
40 grams bonito flakes.
Lightly wipe the surface of the kelp with a tightly wrung cloth.
Put water and kelp in a pot.
Heat on low heat, and when small bubbles come out from the bottom of the pot (about 7 minutes), remove the kelp.
When the kelp soup stock boils, add bonito flakes and simmer on low heat for 1 minute.
Set a colander on a bowl, spread a paper towel on it, and strain the soup stock.
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Transfer the stock to a food storage container and store in the fridge. It can be used for 2-3 days.