There are not many foods as complex as the foundation of Japanese nihon Ryori as dashi.

Simple yet complex, take bottled water and soak kombu from Hokkaido and I use Rausu Konbu but there are various types:

https://mesubim.com/2013/02/10/rausu/

Just after the initial softening of kombu – soaking it in water room temperature for 40 minutes. I then make dashi out of it by adding fish shavings Katsuo and bringing it up to near a boil at 85°C.

Then I fish the kombu out of the pot and bring back to room temperature and the liquid is now a simple dashi. And I cut the daikon into wedges all the same size.

I stain the wedges in a pan using shoyu and de-glaze with mirin to give them a glistened look. This is my own technique and it isn’t something I verified with chefs. I simple do it because I want the daikon to be golden coloured and absorb at first concentrated flavours.

Then the next step is making a custom “brodo” con dashi by adding a small amount of shoyu and either mirin, sake, or “zarame” sugar and bringing to a slow simmer. The taste is a chef’s decision and each person can decide what he prefers. The adding of these ingredients is complex to get right and it takes practice. You cook the daikon until you have the texture you need.