Wash the rice in a bowl or under running water in a mesh colender.
Transfer the rice to a medium-size sauce pan.
Add water and bring to a boil.
Lower the heat to medium-low, cover the saucepan with a lid and let it simmer for 15 minutes. DO NOT OPEN THE LID. If the rice steams too much, lower the heat.
Take the sushi rice from the heat and let it stand COVERED for 10 more minutes.
Transfer the cooked rice into a large bowl and add rice vinegar. Using a wooden spoon, gently mix the rice without breaking it too much.
Serve.
Notes
Use the right rice. Japonica short-grain rice is the best.
Rinse the rice before cooking.
Do not open the lid until the cooking cycle is finished.
Do not over-whisk the rice when seasoning and use a wooden spoon.