About 400 years age, Sorin Otomo, the feudal proprietor of the area, encouraged the active trading with the western countries. The seedling of the tree came from Portugal, which sound was corrupted to Holto. The tree is designated as a prefectural tree of Oita. There are many sculptures on the walls and beams of the Gate. It is very interesting to see them.
Fine sculptures are everywhere on beams and ceilings.
It includes many kinds of evergreen trees such as Kojii, Black trunk, oak, and camphor. The forest is also a bird sanctuary. The gate is usually closed firmly. This is the public entrance to the main building. Actually, some branches of tree are inserted into the ground to serve as tying place for written oracles that bend the smaller twigs.