First wash 4 cups rice thoroughly. Give a little water to the rice and move the pot back and forth. Then pour off the water. The remaining water must be carefully sqeezed out, then again add water, wash and sqeeze it out. At first the water will be a little white of bran; wash until water stays clear. Then you add 4 cups water (the same amount as rice used) and add a small sip (10%).
Cover the pot with an air tight lid and cook for 8 minutes at high heat (switching level 3, or 12, depending on the type of stove). Then turn down to level 1 and simmer 7 minutes without opening the lid however. Turn off the heat and let the rice settle for 5 minutes. Finally place the closed pot in cold water, so that the rice can break loose from the inside of the pot.
Tilt the rice into a round wooden bowl and pour 100 ml sushi vinegar over the rice. Stir quickly and thoroughly to mix the rice and the vinegar, break up clumped rice balls and mix them with the sushi vinegar. Now fan the rice with a fan or sheet of paper and then cover the lukewarm rice with a cloth.
When you can cook and acidify sushi-rice well, then you are already a master.