Wash the wakame and soak it in water for 3 minutes. Drain well and cut into bite-sized pieces. Slice the green onion diagonally into 1cm pieces.

In a pot, combine the dipping sauce ingredients (water, sake, mirin, soy sauce, dashi powder) and bring to a boil over medium heat. Add the pork and skim off any foam. Then add wakame and green onion, simmering on low heat for 5–6 minutes.

In a separate pot, boil plenty of water and cook the soba noodles according to the package instructions. Drain and rinse under cold water to cool, then drain again.