Ieyasu died in 1616, but the continuity of Tokugawa rule was not in much doubt since he had transferred his titles - including that of shogun - to his son Hidetada in 1605. Until his death however, he continued to rule through his son. Hidetada followed this hallowed Japanese tradition by transferring formal power to his son Iemitsu in 1623 but remaining in charge until dying in 1632. Although Hidetada was no wimp, Ieyasu was a hard act to follow and poor Hidetada doesnt get much credit for anything. Iemitsu, however, does. It was his decision to close the country. He also required the individual daimyo to spend every other year in Edo and when not there, their families (wife and kids) had to be there. Somehow, I doubt that the thought of Mrs. Joe Daimyo buying it acted as too much of a deterrent, but maybe Im just old fashioned. By the way, this alternate attendance is called sankin kotai and is very important. We will talk some more about it later. Ieyasu was fairly tolerant of Christianity until 1614 when he began enforcing a ban on foreign religions (a.k.a. Christianity). Iemitsu continued the persecution and of an estimated 300,000 Christians in 1614, between 5,000 and 6,000 were martyred by 1640. Ieyasu and Iemitsu believed that Christians were a threat to their absolute control, a not unreasonable view given Christianitys emphasis on Gods law being above human law. A peasant rebellion, the leaders of which were Christian, confirmed Iemitsus worst fears. The rebellion (in the Shimabara Peninsula) lasted from 1637-38 and it was only one year later that Iemitsu closed Japan off from the rest of the world. This policy of national isolation is known as sakoku and lasted until Commodore Perry. It included foreign (read Western) books, but that ban was lifted in 1720 for books of a non-religious nature. Of course, since nobody in Japan knew anything about European culture or religion, some books, predictably, were banned just for mentioning religion.