The contribution of cereals to economies is undoubtedly very important and has many dimensions in terms of use of cultivated areas, agricultural production, nutrition, domestic and foreign trade and national income. In this study, we examined the characteristics of agricultural production in Okayama prefecture from the viewpoint of grain, beans and potatoes excluding rice, wheat and barley in the long term. These are undoubtedly supposed to have a certain role in complementing the function as the staple food of rice and wheat, etc.Also, according to our literature investigations, researchers have not focused on this context for Okayama Prefecture by not spending enough attention in the past. Therefore, we focus on these subjects in this paper by examining a historical significance. It is observed that some planting area and yield of crops have drastically reduced in Okayama prefecture.