In a medium saucepan, add water and dashi packet (some brand of dashi packet may ask you to add the packet after boiling). If you are using dashi powder, bring water to a boil and stir in the dashi powder and it’s ready to use.Bring it to a boil over medium high heat. After boiling, reduce the heat to medium low and simmer for 5 minutes.Discard the packet and dashi is ready to use.Put 1 Tbsp. of miso in a ladle (or strainer) and blend it with dashi until it is thoroughly mixed. Continue this process until miso is all used. Usually each cup of dashi, you will need about 1 Tbsp. of miso. If you add tofu in your miso soup, tofu dilutes the soup a little bit so you might want to add ½ Tbsp. more miso.Cut tofu into ½â€ (1 cm) cubes and add to the soup. Stir gently without breaking the tofu.Soak dried wakame in water to rehydrate for 10 minutes and drain well.Finely slice the green onion and put the wakame and green onion in each bowl.Return the miso soup to a slight simmer until heated through and pour into the bowls. Be careful not to boil the miso soup because miso will lose flavor.