Udon is a type of noodle in Japan. The ingredients are super simple: water, flour, and salt. Traditional Udon is considered to be a healthy food because it doesn't have any preservatives, which means you have to put it into fridge to preserve it. There are warm version Udon and cold version Udon. In this picture, it is cold version. General speaking, now days people don't make Udon at home, just buy it from shop. If you want to learn how to make it, please check www. washo-cooking.com.