Mix the rice seasoning until the sugar and salt are dissolved, then add to the hot rice and mix well to cool enough to hold by hand. Vinegar is also water, so you have to put it in hot rice and blow away the steam to prevent the rice from getting soggy. Add and mix well, fan it and let it cool while blowing the steam. If it's too cold, it won't shape well, so just let it cool enough to touch with your hands.

Grill smoked duck while the rice cools. Bake, spread out, and let cool while removing some grease.

Squeeze the rice into the right size and shape it, then spread wasabi in the right amount. It's good to put it on as much as you want. When you touch it, even if you wear plastic gloves, rice sticks all over the place, so it's best to pour water into a small bowl next to it and stick it together with your bare hands.

You can put the grilled smoked duck on top and shape it well, then wrap it around the long-cut seaweed, and serve it with mustard or other decorations depending on your taste.