Combine the sugar, salt, a few sprinkles of MSG and the dashi in a 1 litre pot & bring to a boil over high heat. Add the taro potatoes, stir gently, & reduce the heat to low. Simmer, uncovered, for 6 to 7 minutes, then remove from heat and cool to room temperature. Pass the sheet of nori over a flame on one side to intensify its color & flavor, & crumble it coarsely on a sheet of wax paper. With tongs, remove the taro potatoes from their liquid and roll them one at a time in the crumbled nori to coat their surfaces evenly. Serve at room temperature either as part of a picnic box or as part of a Japanese meal.