Between the 17th and 19th centuries, the Japanese government closed its borders to the outside world in an attempt to become more powerful. Foreign books were banned, people could not travel, and foreigners were not allowed to enter the country. One result of this isolation was the flourishing of sangaku--wooden tablets inscribed with intricately decorated geometry problems that were hung beneath the eaves of Shinto shrines and Buddhist temples all over Japan (Fukagawa & Pedoe, 1989). The hanging of tablets in Japanese shrines is a centuries-old custom, but earlier tablets generally depicted animals. It is believed that the sangaku arose in the second half of the 17th century, with the oldest surviving sangaku tablet dating from 1683. About 900 tablets have survived, as well as several collections of sangaku problems in early 19th century hand-written books or books produced from wooden blocks. Although their exact purpose is unclear, it would appear that they are simply a joyful expression of the beauty of geometric forms, designed perhaps to please the gods. This article describes a small selection of the sangaku problems and leaves the reader with several unanswered questions: How did the custom originate? Were the problems devised by the presenters? Where solutions were not given, how did the presenters intend the problems to be solved? To really enter the minds of the temple geometers, it would be necessary to explore in greater depth the mathematical techniques that they had at their disposal during the 17th-19th centuries.