Jizo is the Japanese name of one of the most popular bodhisattvas in Japan and is usually used in conjunction with the honorifics O and sama. Jizo statues are a familiar sight along roadsides in Japan. The Jizo bodhisattva originated in India and was introduced into Heian-period Japan from Tang China. Veriation of Jizo became at a time when the end of the world, epitomized by the Buddhist concept of mappo, was thought to be near. Because of the bodhisattva's vow to aid all those who suffer, Jizo quickly became popular among the court nobility and later the common people. It was believed that in the long, long period of time between Sakyamuni's death and the advent of Nyorai, the Buddha of the future, only Jizo remained to protect and save humanity.
Later, with the advent of Kamakura Buddhism, the nobility's veneration of Jizo began to wane, but the common people retained their faith, and figures of Jizo came to be placed at village boundaries, crossroads, and along roadsides. The fond appellation, Ojizo-sama, is believed to have taken hold around this time, particularly because Jizo was thought to have a special affinity for children.
Figures of Jizo are often dressed with a bib. This practice is believed to have begun when grieving parents who had lost a child put the deceased child's bib on a Jizo statue in the hope that he would protect their child in the other world. Related to this is the custom of Jizo-bon, an event to commemorate Jizo as the protector of children, which began in Kyoto and spread to the surrounding Kinki region sometime in the Edo period(1603-1867). Jizo-bon is a time for children to honor Jizo, but it is also celebrated as a festival for children. There are more than 5,000 statues of Jizo in Kyoto alone.
Reference:Hayami Tasuku, Kannon, Jizo, Fudo. Kodansha, 1996.