1 Cup of Japanese short grain or California Japanese style medium grain. I use Nishiki
Water or, as I prefer, Dashi according to rice packet instructions. I use a 1:.1.3 rice to water ratio.
Sushi Vinegar (instructions below)
Note:
Whether you use a rice machine or have a non-automated approach, follow the instructions on the packet. It basically involves thoroughy rinsing the rice, followed by a soaking period, then a cooking period and finally a resting period. There is no shortage of info online as to how each is accomplished. The same is also true of how to convert rice into sushi rice. The basic process is adding sushi vinegar and attaining a temperature close to body temperature. This video by Kunihiro starting at the 4:40 mark describes this very well.
What is distinctive about making Japanese rice is the fact that it is rinsed repeatedly to remove the rice starch, it is then soaked for 20 to 30 minutes and the 1:1.3 liquid to rice ratio is so different than the Western standards.
The vinegar component is where individual taste comes in. There are many different ideas as to the proper ration of vinegar to salt to sugar. Different people also have different ideas as to how much of this mixture should be added to rice. My own ration follows:
For 1 cup of rice, I add 70ml. of the following mixture. Measure the mixture as the rice vinegar dissolves much of the sugar and salt.
50 ml unseasoned rice vinegar
30 grams of sugar
6 grams of salt
3 grams of Kombu (dried Kelp)
Sushi rice
With a whisk, dissolve the sugar and salt in the rice vinegar
Add a piece of Kombu
Store overnight in the refrigerator
Discard Kombu in the morning.
Make rice as you would normally
Incorporate the vinegar according to these instructions by Kunihiro