Isn't everyday rice day?

August 18th annually is "Rice Day", Kome no hi, 米の日. Moreover, the 18th of every month is also "Rice Eating Day," which was established by Mie Prefecture in October 1978. In addition to August 18th, the anniversary date can also be August 8th, or the 8th, 18th, or 28th of each month. 

Why the 8th, 18th and 28th? 

The date was chosen because the kanji character for "rice" (kome) can be broken down to "88" (88). Another reason given is supposedly it takes 88 steps to harvest rice.

Rice in Japan 

Rice is a staple in Japan. Reportedly, rice cultivation begun in the late Jomon period.  During the subsequent Yayoi period, wet rice farming became the main method of production, making it possible to store grain for longer periods of time. 

Prefectures with high rice production in Japan include Niigata, Hokkaido, Akita, Miyagi, Fukushima, Yamagata, Ibaraki, Chiba, Tochigi, and Aomori. Rice varieties widely distributed in Japan include Koshihikari, Hitomebore, Akitakomachi, Tsuyahime, Hinohikari, Sasanishiki, and Kinuhikari.