Remove the head of the sardines and cut into halves. Remove the guts and the scales while washing and pat dry. Slice the banno negi on the diagonal, cut the ginger into thin slices (usu-giri), and halve the red chili pepper. Rehydrate the wakame and drain.
Arrange the sardines in a pot and add the (A) seasonings, the ginger and the red chili pepper. Bring to a boil and flip the sardines over. Add the (B) seasonings, cover with a drop-lid and let simmer over low heat for about 30 minutes.
Simmer the (2) sardines until there is almost no liquid and then add in the green onion, the wakame, and the lemon juice.