While the chicken is in the oven, rinse the dried kombu under cold running water. Soak the kombu in a large stock pot for 30 minutes in 2.5 litres/4½ pints cold water. The kombu will triple in size.

Dashi most commonly utilizes a combination of kombu (kelp seaweed) and katsuobushi (dried bonito flakes), but other ingredients used to make dashi are shiitake mushrooms and niboshi (small dried fish) ...