For mountain yam or "nagaimo" 長芋 fritter (I am not sure what is the right name for this dish, "fritter" is not quite right but piccata is also not right), peel and slice the yam in 1/2 inch thick rounds (I made 4 rounds). Beat one egg and mix in 2 tbs of finely chopped vinegared ginger root (called "Gari", the type you have at the sushi bar) and dried "aonori" powder (1 tsp). Dust each round with popato starch and then coat with egg mixtures. Pan fry in a frying pan with a small amount of vegetable oil (I used light olive oil) for 2-3 minuts on each side until crusts are formed. Eat with salt or soy sauce (I used salt).
I am not sure that the addition of a "Yuzu-kosho" to "tsukune" was a success. It does not have enough fresh "yuzu" flavor to make a big difference. But as far as "tsukune" goes it was more than OK. The mountain yam fritter has a very nice crunchy texture inside and nice eggy crust with ginger and aonori flavors. Very nice texture and flavor contrasts.