Score corn husk lengthwise into three even sections. Carefully, peel husk down the cob, to leave husk attached at the bottom of the cob. Separate the three sections of husk. Take the left section and cross it over the middle section. Then take the right section and cross it over the middle. Repeat this braiding process once or twice depending on the length of the husk. Tie the end of the braid with a thin strip of corn husk or with butcher’s twine. If braiding is too labor intensive, simply gather the sections of husk together and tie with butcher’s twine so they stay together in a bundle. Pull off as much silk as possible from the cob and then rinse with cool water to wash away any remaining silk. Repeat with remaining corn cobs.
Place softened butter in a mixing bowl. Using a rubber spatula or wooden spoon, stir butter to soften. Add remaining ingredients and stir to combine. When ready to use, barely heat butter so that it just softens to a glaze, but does not separate.
To Grill Corn:
On a medium-hot charcoal fire, grill corn just until it starts to color, dip corn in soy sauce, and continue grilling, turning often to create an even caramelization. Repeat the process of dipping and grilling corn until corn is as charred as you like and takes on a deep mahogany color from the soy sauce. Just before removing corn from the charcoal grill, brush with robata-butter until melted and glistening. Sprinkle with gomashio.
Note: Use any leftover butter for brushing onto grilled steaks, chops or fish filets.