You need a water and vinegar mixture to:

- rinse the bowl in which you put the boiled rice, so the rice will not stick to the bowl.

- dip your hands into while making sushi, each time you pick up some rice by hand. This prevents the rice from sticking to your hands.

 

The bowl should be large enough to dip your hand into it.

Pour water and rice vinegar into a bowl:

take 3 tablespoons of rice vinegar to 1 cup of water.