For our answer, let us turn our attention to the nation famous for horse-riding called Bohai, better known as Mongolia. Even though the number of official meetings was 34, private meetings occurred often. From the meetings between Pohai and Japan, the idea of riding horses was obviously introduced. It is better that draft horses not have so high a body. Horses used for riding, however, require a reasonable height and speed.
Speed is also an advantage for horses used in battle.
Therefore, the background of the existence of excellent horses in northeastern Japan probably started with the meetings with Bohai. If so, such excellent horses must exist, by the same reason, in the Hokuriku area which has a southern seashore along the Sea of Japan. However, it was very difficult for horses to travel any further. In the business of transporting and selling horses, it is always desirable to complete the transactions as soon as possible, and at the nearest location. This actually happened with horses that were transported to Hokkaido or other parts of northeastern Japan.