Normally, udon is served in hot soup primarily made from skipjack tuna broth and soy sauce. During the hot and humid summer here, chilled udon is served with cold soup, bringing a sense of coolness both physical and mental, and therefore is a popular food.

Udon is made of flour, a little salt, and water. Interestingly, however, many Japanese people of today associate flour with bread rather than with udon. In the earlier days when bread was not yet so popular here, the order of the association was reversed.

The primary nutrient of udon is carbohydrate, which in the body is transformed into glucose and glycogen, source of energy for the brain and other bodily parts. Also, udon is digested and turned into energy very quickly and efficiently, and is therefore used as a means of quickly enhancing concentration. All this makes udon a preferred night snack among students preparing for college entrance examinations and also a handy lunch meal for hurried workers.

The average annual production of wheat in Japan is approximately 700,000 tons, about 60% of which is produced in Hokkaido. Japan's self-sufficiency ratio of wheat is only about 11%, with the remainder imported primarily from the Unites States, Canada and Australia.