COOK THE RICE. Rinse the raw short-grain rice until the water runs clear. Cook using your preferred method. If you aren't sure how to cook rice, watch How to Cook Perfect Steamed Japanese Rice.
PREPARE THE MYOGA. Slice the myoga (1 bulb) in half lengthwise, then slice very thinly into half-moons. Soak the slices in a small bowl of cold water for 2 minutes to remove excess bitterness, then drain and dry thoroughly with paper towels.
PREPARE THE SHISO. Stack the perilla (3 leaves) on top of each other, roll them tightly into a small cylinder, and slice across to create delicate, thin ribbons (chiffonade). Gently pat dry if there is any moisture.
GRIND THE SESAME. Toast the sesame seeds over medium-low heat until golden and fragrant. Turn off the heat just before you think they are ready and allow the residual heat in the pan to finish the cooking. Transfer the seeds to a mortar and pestle and grind until they resemble grains of sand.
SEASON THE RICE. Transfer the hot cooked rice to a wide mixing bowl. Sprinkle the sea salt (1.5g) and the optional soy sauce (1.5ml) evenly over the surface. Use a wet wooden rice paddle (shamoji) to slice through the rice on an angle, distributing the seasoning without mashing the grains.
FINISHING & SERVING. Add the prepared myoga, shiso, and toasted white sesame seeds (4.5g). Lightly bruise the sesame seeds between your fingertips as you sprinkle them in to release their essential oils. Gently fold the ingredients into the rice using a cutting and flipping motion. Serve immediately while warm and highly aromatic.
SUBSTITUTIONS. Myoga and shiso are difficult to find in most areas outside of Japan. That is no reason not to make this recipe. You can substitute ginger for the myoga, though you will want to adjust the amount to taste: the flavor and aroma are much more pungent. For the shiso, you can substitute several other herbs. Two immediate suggestions are cilantro or mint.