The term Yōga is used in Japan to refer to Western-style art. It is often used to specifically denote oil paintings but more widely can refer to a range of imported methods, such as watercolors, pencil drawing, etching and lithography. It is this concern with materials that has traditionally distinguished Yōga from Japanese methods of art production, rather than reference to Western pictorial devices such as fixed-point perspective. As a result of missions from Europe arriving in the 16th century, Japan’s earliest forays into Yōga were Christian paintings, at least until the religion was outlawed under the Tokugawa Shogunate, which also implemented a policy of national seclusion. But it lifted its ban on foreign books in the early 18th century, and a limited number of painters, notably Satake Shozan, Hiraga Gennai and Shiba Kōkan, turned their hand to oil painting. But the category of Yōga was not established until after the full-scale opening of Japan to the outside world in the mid-19th century. In 1856 the Shogun founded a bureau for research into Western studies, including art (the Bansho Shirabesho). One of its students, Takahashi Yuichi (1828–1894), later became a pioneer of Yōga.