You can vary the kinds of miso you use, or combine different kinds. In fact, you can vary just about everything with this recipe! I usually aim for 2 main ingredients plus a garnish, in addition to the dashi and miso. Some other ingredients I especially like include thinly sliced carrot or daikon, cut into seasonally-appropriate shapes with mini-cookie cutters (like flowers or leaves), thinly sliced mushrooms, enoki-take mushrooms, wheat gluten (available in small balls or other shapes at Asian groceries), and sansho pepper. The wakame, tofu, and green onions are our favorite, though.