Method:
Combine miso, sake, mirin, sugar and niban dashi in a double boiler over low heat. Stir until smooth and thicken to a paste consistency, about 10 minutes, stirring frequently.
Remove tofu from package and wrap in paper towels. Place on a plate and place a plate on top, to press water out of tofu. Place tofu block longways and cut in half horizontally. Rotate each half 90 degrees and cut into 3/4-inch slices. Carefully insert two bamboo skewers into each slice so that they angle slightly.
Grill over very hot coals for about 3 minutes on each side. It is helpful to place bricks on your grill to rest skewers on so that tofu doesn't touch the grill. After turning to second side, spread miso sauce on the already grilled side. Turn again and grill miso sauce side for another minute. Top each with one of the garnishes.