Sushi rice is sweetly vinegared, and the delicate taste goes so well with raw fish. Use short/medium grain rice and steam in a rice cooker is easiest. Wash the rice first, and drain for at least 30 minutes before steaming.
For 500g uncooked rice, you will need 120cc of rice vinegar, 2 tablespoons of sugar and 1 teaspoon of salt. Mix the rice vinegar (use only rice vinegar) , sugar and salt in a saucepan and heat to dissolve solids. When the rice is cooked, place in a hangiri, or unfinished wooden bowl and mix in the vinegar mixture. Use a spatula to mix in the vinegar with a cutting action so you don’t squash the rice grains.
Fan the rice to make it shiny. Leave to cool covered with a wet cloth.
Here’s Masako talking about sushi rice on Food Safari
by Masako Fukui, Kei’s Kitchen