* 6 cups of water
* 10 cm square konbu kelp

* 40g dried bonito flakes
Soak the konbu kelp in water

Turn the heat on high

Remove the kelp just before the water comes to a boil

Add the bonito flakes
Boil again and turn off the heat 

Let it stand until the flakes sink to the bottom of the pot

Remove the flakes from the pot