Start by opening up your pack of konbu kelp and wiping it down with a damp cloth to remove any impurities from the surface.
Add a piece of konbu kelp approximately the size of a postcard with the water into a large pot and let it soak for about 20- 30 minutes in the cold water.
Turn on the heat and allow the water to boil slowly.
Just before the water boils, remove the heat and add your katsuobushi to the pan.
Without letting the water fully boil over, allow the katsuobushi to simmer in the water for 1 minute.
Remove the konbu and katsuobushi from the pan and strain through a fine sieve into a clean jug or pot.
- To make vegetarian version of this classic Japanese dashi stock, simply substitute the katsuobushi bonito flakes for dried shiitake mushrooms and allow the flavour of the konbu kelp and shiitake mushrooms to infuse with the water. Allow the ingredients to soak in cold water for a few hours before heating and straining like the katsuobushi recipe. You can then use the shiitake for any number of Japanese dishes afterwards too.