In Japan, the rice used to make Nori-Maki is seasoned with a blend of rice vinegar, sugar and salt. In macrobiotic circles, plain cooked brown rice or a combination of brown rice and sweet brown rice is most often used. Short-grain white rice also makes delicious nori-maki. If you want to try seasoning your rice, try mixing brown rice vinegar, shoyu, and mirin in a ratio of about 3:1:1, put it in a spray bottle, and lightly spray the mixture on the rice after you have spread it on the nori, but before rolling it.
To prepare simple, home-style nori-maki, toast nori briefly (unless you are using sushi nori, which is pretoasted). Place the nori on a sushi mat or countertop. Spread about 1 1/2 cups cooked rice evenly over the nori, leaving uncovered 1 1/2 inch at the top and 1/2 inch at the bottom.
Various ingredients can be used for the center of nori rolls. A most simple yet delicious roll can be made using only umeboshi paste - rub umeboshi in a line from left to right across the center of the rice. If desired, vegetables such as thin cucumber strips and/or parboiled carrot strips can be placed next to the umeboshi paste. Shiso (perilla) leaves, which come pickled with umeboshi plums, or shiso senmai (whole pickled shiso leaves) are especially good.
Starting at the edge closest to you, gently but firmly roll into a tight cylinder. Let the roll rest on its seam. (If necessary, dampen the top edge of the uncovered nori to seal the roll.) Cut the roll in half, and each half into 3 or 4 pieces. Clean the knife between cuttings.
Other center ingredients, such as pickles; natto mixed with a little shoyu and minced scallion; sauerkraut; avocado; or very fresh, raw salt-water fish and wasabi, provide a variety of interesting tastes and textures. If using wasabi powder, add just a few drops of water to form a paste. It is strong, so rub only a thin layer across the rice.
Depending on the filling, you may or may not need a dipping sauce. More flavorful rolls can be enjoyed as is. Those made with wasabi and unseasoned vegetables or fish are best dipped in a mixture of 3 tablespoons kombu stock or water, 3 tablespoons shoyu, and 1 tablespoon mirin. Combine these ingredients in a small saucepan, simmer for 1 minute, then cool to room temperature. Serve dipping sauce in small individual shallow dishes.