Osouji is a Japanese custom that is typically done at the end of December. The word Osouji translates to "big cleaning/cleanup." Osouji is done before New Year's Day and is done to purify the home, work place, schools, and neighborhood. This custom was first seen as a purification ritual to symbolize cleaning not only one's house, but also the mind and soul.
Osouji originated from another Japanese custom, known as Susuharai which translates to "Soot Sweeping." Susuharai is an annual ritual also performed in December that is symbolic when greeting the Shinto deities of the New Year. As seen in the images below, a team of people are cleaning the Matsumoto Castle. They use long bamboo sticks with brooms on the bottom to sweep the walls and clean the roof tiles. To tie it all together they hang a Shimenawa which a huge straw rope that are located on gates and the castle tower. The shimenawa acts and represents a barrier between our world and the world of the gods. The rope also prevents evil spirits from entering. These ropes are hung all year around at Shinto shrines, but specifically hung during this time by many businesses and homes.