Chop the komatsuna into bite-sized lengths. Slice the aburaage in half lengthwise, then cut into 1-cm wide strips. Grate the ginger without peeling, then strain the juice.

Put the dashi soup stock, mirin, and usukuchi soy sauce into a pot, and bring to a boil. Add the komatsuna stalks, greens, and aburaage, in that order, then simmer over medium-high heat without stirring.

Once it comes to a boil, stir it up. When the stalk of the komatsuna reaches your desired tenderness, add the shirasu and strained ginger juice, stir it up, then turn off the heat.