Start by washing the rice. To do this, put rice in water and work with hands or stir until water becomes milky in color. Drain water and add more. Do this four to five times. Drain water from rice.
In a pan with a tight fitting lid, add the rice, water, and kelp. bring to a boil over medium heat, removing the kelp just before the boiling point. Cover the pan and simmer for about 10 minutes or until all the water is absorbed. It is very important to not lift the lid at any time while the rice is cooking.
Turn off the heat, remove lid, and cover the pan with a dish towel. Leace to cool for 10 minutes.
Meanwhile, mix together the ingredients for sushi vinegar in a pan. Heat until the sugar dissolves, then remove from the heat and pour the sushi vinegar into a cool bowl.
Using a wooden rice paddle, spoon the rice into a rice tub or bowl. spread it out evenly, then run the paddle briefly through the rice cutting it first from side to side, then from top to bottom.
Continue cutting, never mashing or stirring the rice, adding the sushi vinegar a little at a time.
Cover and let rice cool to room temperature. (Sushi rice is traditionally served at room temperature. If the rice is warm, the vinegar will distill off.).