In any case, this is not a recipe. I just prepared nattou as usual using the seasoning liquid and mustard packets that came with the natto. I just added chopped scallion and mixed it using my nattou mixing contraption well. I removed the stone, skin and cubed the avocado and dressed it with lemon juice and placed the pieces on the endive leaves. I added a few small scoops of soft otokomae tofu and placed a dab of real wasabi on top. Just before eating, we sprinkled on soy sauce and mixed with a small spoon. We ate this with our fingers; picking up the endive leaves. (A word of advice: Start eating from the soft tip of the leaves, otherwise, the leaves will not hold the contents. You do not want to spill nattou on your shirt).
This is not bad at all. The combination of avocado, silken tofu, and nattou is remarkably good. With nattou, sake is the recommended libation.