By custom, the "onbashira" are replaced every six (traditionally reckoned as seven) years, in the years of the Monkey and the Tiger in the Chinese zodiac. In Suwa Shrine, this occurs during the , which also functions as a symbolic renewal of the shrine's buildings. During the festival, sixteen specially-chosen fir trees are felled and then transported down a mountain, where they are then erected at the four corners of each shrine. Festival participants ride the "onbashira" as they are slid down the mountain, dragged to the shrine, and raised, and the festival has the reputation of being the most dangerous in Japan due to the number of people regularly injured or killed while riding the logs. This festival, which lasts several months, consists of two main segments, "Yamadashi" and "Satobiki". "Yamadashi" traditionally takes place in April, and "Satobiki" takes place in May.