Age of Calamity (厄年)
As propagated by Onmyodo (the traditions of Yin-Yang divination and astronomy), a person is believed to suffer misfortunes during their age of calamity.
The tradition of calamitous ages, whose genesis is shrouded in obscurity, but which already existed in the Heian period, still runs deep in Japanese society.
Summary
This is why people practice 'yakubarai' (exorcism of bad luck) or 'yakuyoke' (avoidance of bad luck) at their ages of calamity, in order to pre-empt adversity or misfortune by the help of Shinto and Buddhist deities. Even if nothing bad happens, physical deterioration may manifest itself as decreased strength or slower reflex at the ages of major calamity. People of these ages may need to pay more attention to their health.
In some places, the ages of shichigosan (a celebration for three-year, five-year and seven-year old children) are also included in the calamitous ages in their broadest sense. In this case the earliest age of calamity is the age of three (in Japanese age reckoning) for both men and women. The notion of the age of calamity is not limited to countries where the traditions of Yin and Yang divination and astronomy, Shinto or Buddhism have been spread. It is also found in Christian countries like Britain and Spain and in Islamic countries such as Egypt and Turkey.
Widespread and well-established in each region, it ranges from simple pilgrimage for the purpose of avoiding bad luck to a community-wide celebration.
There is also a custom of counting calamitous ages by multiplication: the age of 25 expressed as 'a calamitous age of five times five.'
Famous Buddhist Temples and Shinto Shrines for Avoidance of Bad Luck
Kanto Region
Three great Kobo Daishi-related temples in Kanto
Soshu-ji Temple
Soji-ji Temple (Adachi Ward)
Heiken-ji Temple
Myoho-ji Temple (Suginami Ward)
Haijima-daishi Temple
Kanpuku-ji Temple (Makino, Katori City)
Tokai Region
Hattasan Sonei-ji Temple
Owari Okunitama-jinja Shrine
Mishima-taisha Shrine
Kinki Region
Iwashimizu Hachiman-gu Shrine
Kiyoshikojin Seicho-ji Temple (commonly known as Kiyoshikojin)
Mondoyakujin Toko-ji Temple (commonly known as Mondoyakujin)
Taisho Kannon-ji Temple (commonly known as Abiko Kannon)
Tainohata Yakuyoke Hachiman-gu Shrine (commonly known as Tainohata Yakujin)
Tachikisan-ji Temple (commonly known as Tachiki Kannon)
Chugoku Region
Yugasan
Wake-jinja Shrine
Shikoku Region
Yakuo-ji Temple (Minamicho) (the 23rd temple of Shikoku Pilgrimage, Tokushima)
Henjoin-Temple (Imabari City) (Kikumacho, Imabari City, Ehime Prefecture)