Sakabashira (a pillar erected upside-down) (逆柱)
Sakabashira' or 'sakasa bashira' refers to one of superstitions about Japanese wooden structure (architecture),
It is said that when a timber is used as a pillar, it was erected upside-down, making the roots on the top.
It is said that the pillar erected upside-down shakes its house or furniture at night. It was considered as abhorrence, because it makes the fortunes of a family be on the wane and brings misfortune like the fire or ominous incidents.
There is a story in a book, "Saikaku oridome"(a book which describes variety of subjects and aspects of daily life of ordinary people) written by Saikaku IHARA. The story goes as follows; a couple living in a house located in front of Chohoji-Temple was annoyed by strange phenomena caused by a pillar erected upside-down.
They heard a big strange noise like beams collapsing almost every night, then, eventually, they moved out. Also, in Odawara City, during a ceremony in a merchant house, people heard a voice saying, 'I 'm choking', so, they searched a room to identify where the voice was coming from.
It turned out that the voice was coming from a pillar in a room floored with tatami mats and they found that the pillar was erected upside-down.
Yomeimon' (Yomei gate) erected in Nikko Tosho-gu is famous for its 'sakabashira'. Visitors can identify that only one of its pillars was erected upside-down, because it has carving patters upside-down. However, it was erected in this way not by mistake but on purpose, following an oral tradition, 'When a construction is completed, it begins to collapse'. People wanted to avert misfortune by intentionally leaving the pillar unfinished. Therefore, in a sense, the pillar was erected upside-down with the view of warding off evil, which shows it has no relation to an oral tradition of yokai.
Tsurezuregusa' (a collection of Japanese essays) written in the Kamakura period stated that something perfect is not good at all. It continued to say, 'Therefore, when the Imperial Palace precincts were constructed, a part of them should be kept unfinished'. It is said that in the Edo period, when a house was built, three tiles should be left unused.