Lightly wipe the surface of the dried kombu with a damp paper towel. Place the kombu and water in a pot and let it sit for 1 hour.

Cut the napa cabbage into bite-sized pieces. Trim the roots of the mizuna and cut into 4cm lengths. Trim the roots of the enoki mushrooms and separate them. Slice the green onion diagonally into 1cm pieces.

Heat the pot with kombu and water over low heat. Remove the kombu just before boiling. Increase to medium heat and add napa cabbage, mizuna, enoki mushrooms, and green onion. Simmer for 2–3 minutes.

Dip each slice of pork belly into the broth individually to cook.