Hidetada nominally assumed the title of shogun in 1605 when his father voluntarily retired, but as long as Ieyasu lived, Hidetada’s role was to learn from and implement the policies of his father. He was a careful student, who watched his father build his realm for the family and the bakuhan system.
Among Hidetada’s achievements were the continued organizing of the Bakufu and development of domestic commerce. Both of these ensured the Tokugawa family’s political and economic dominance in Japan.
In 1614–15, Hidetada helped his father in leading a victorious campaign against Osaka castle that ended the residual power of the Toyotomi family. From 1616 onward, he boldly tamed the domains of vassals who might challenge his authority.
Domestic commerce grew with the expanded control of Hidetada’s government. However, he was highly suspicious of foreign traders, missionaries, and those Japanese who had converted to Christianity.
Tokugawa Hidetada reinforced Ieyasu’s ban on Christianity. In 1617, he had four missionaries executed. He later ordered the execution of 120 missionaries and Japanese Christians and banned any import of books related to the Christian religion.
Hidetada’s severe reservations about all things foreign extended to their trading ships as well. In order further to regulate foreign presence, he ordered all foreign ships, other than Chinese, to dock only in the ports of Nagasaki and Hirado.
The British had already pulled out of Japan because of nonprofitable trade relations. Hidetada severed all relationships with the Spanish, of whom he was highly suspicious because of their Christian influence. Hidetada effectively isolated Japan, a stance his son terminated when he became shogun.
Hidetada had established a relationship with the imperial family through the marriage of his daughter to a member of the royal family. This relationship further solidified the base of the Tokugawa family. In 1623, Hidetada abdicated in favor of his son Iemitsu but continued to influence policy of the bakufu as retired shogun until his death.