From the book of changes

In the hexagram, the upper hexagram is the earth, and the lower hexagram is the mountain

The humble trigram is on the earth, and it looks like a mountain

Yamamoto is tall, but it is underground, so it cannot be shown. This is like a person with high morality, but can consciously not show it. It symbolizes modesty and humility

It is the only hexagram in the sixty-four trigrams that all six auspicious signs are auspicious. It implies that a gentleman with modest virtue can prosper in everything, and that he can be modest from beginning to end