shogun, the eighth Tokugawa to hold that office (1716–45). He was extremely capable and, though conservative, was interested in science. In 1720 he allowed European books, hitherto excluded, to be imported by Dutch traders at Nagasaki. Religious books were still banned. He also had a Dutch–Japanese dictionary compiled. The introduction of rangaku (Dutch learning) had a profound effect on what had been a closed world. There was particular interest in medicine, cartography, and military science. Yoshimune worked to increase the shogun’s authority and improve government finances.