What is it? 
Vinegar made from rice wine or fermented rice.

Are there different varieties?
Rice vinegar can be made from white, brown, black or red rice, all of which are slightly different. You can use whichever for most recipes but white wine vinegar is the most common.

Is it essential?
If you like making Japanese food, you should definitely buy a bottle!

Is it easy to find?
Many supermarkets sell it. You can also find it in Asian food stores and online.

What does it taste like?
It is a bit like white wine vinegar but milder and sweeter.

What is it used for?
Sushi rice, salad dressings, sauces.