Soak kombu with 2 cups of water in a small pot for 30 minutes.

Add tamari, mirin, and maple syrup to the pot and bring water to a boil. Once water starts to boil, remove the kombu. While water is boiling add in the bonito flakes and let boil for 3 minutes.

After 3 minutes, remove the pot from the heat and let it cool for a few minutes until all the bonito flakes sink to the bottom of the pot.

Strain the sauce into a container with a lid and let cool to room temperature before sealing and refrigerating. You want to serve it cold with a side of the grated radish.

Sprinkle green onion and sesame seeds over your sauce, then add some grated radish in before you start dipping. Serve with the cooked soba noodles topped with shredded seaweed.