Temaki

Rinse 300g Japanese short-grain rice thoroughly under cold water until the water runs clear. Drain well and transfer to a rice cooker or heavy-bottomed pot. Add 330g cold water and 5g kombu. Let the rice soak for 30 minutes. Cook the rice according to your rice cooker's instructions or bring to a boil, then reduce heat to low, cover, and simmer for 15 minutes. Remove from heat and let steam, covered, for another 10 minutes. Discard the kombu.

While the rice cooks, prepare the sushi vinegar. In a small saucepan, combine 50g rice vinegar, 20g granulated sugar, and 5g sea salt. Heat gently over low heat, stirring until the sugar and salt are fully dissolved. Do not boil. Remove from heat and let cool to room temperature.

Transfer the warm cooked Japanese short-grain rice to a large, shallow wooden or non-reactive bowl. Pour the cooled sushi vinegar evenly over the rice. Using a rice paddle or spatula, gently fold and cut the rice with a slicing motion, being careful not to mash the grains. Fan the rice with a hand fan or piece of cardboard to cool it quickly to body temperature, ensuring a glossy finish. Cover the sushi rice with a damp cloth to prevent it from drying out.