According to Japanese belief, Sakabashira are the angry spirits of tree leaves which manifest inside houses where one of the pillars has been placed upside-down — that is to say, in the opposite direction of the way the tree was pointing when it was living. These spirits manifest their grudge late at night, and bring misfortune upon those living in the house.

Sakabashira are most well-known for making noises. They creak and moan, imitate the sounds of wooden beams cracking, and sometimes even speak in sentences like, "My neck hurts!" They can cause houses to shake, and the leaf-spirits residing in the tree can manifest as yanari, acting like poltergeists and breaking things around the house. Sakabashira can be so loud that families often move out of a house that is haunted by one, for these yokai cause not only strange noises, but also terrible luck. People who stay in a house haunted by a sakabashira often lose their family fortunes, or even lose all of their possessions to great conflagrations which consume and destroy the cursed house.

It has long been a folk belief that a pillar erected in the upside-down position will bring misfortune to a family, and a sakabashira is usually the result of a careless mistake on the part of the construction crew. In order to prevent this yokai from appearing, folk superstition tells us that a pillar must be erected in the same orientation as the tree had when it was alive. However, sometimes support pillars are actually installed this way on purpose. The reason for this is another folk belief: "The moment a house is completed, it starts to fall apart". As a kind of ward against bad luck, Japanese buildings were sometimes only almost completed, with the final step being left out, or purposefully made into a mistake. The famous Tosho-gu shrine at Nikko is such an example, having been built with just one pillar purposefully pointing in the opposite direction. This same superstition was followed when building the imperial palace — placing the final pillar in an upside-down position. During the Edo period, house builders commonly "forgot" to place the last three roof tiles for the same reason.