Iemitsu Tokugawa was born on 12 August 1604. He was the second son of Tokugawa Hidetada; his mother was the daughter of Asai Nagamasa, a military leader of the province of Omi, and his wet nurse was Kasuga-no-tsubone. In childhood he went by the name Takechiyo.
In 1614-15, when his father and grandfather marched west to attack and overthrow the forces of the Toyotomi family at Osaka Castle, he remained in Edo to guard Edo Castle, though still only a child. With his coming-of-age ceremony in 1620, he assumed the name Iemitsu. In 1623 he journeyed with his father to Kyoto and received commission from the imperial court to succeed his father in the position of shogun.
During the 1630s, he took various steps to consolidate the power of the Tokugawa family and insure the effective functioning of the feudal system of government. In 1633 he drew up regulations making clear the number of troops and armament the hatamoto (samurai directly under the command of the shogunate) were expected to have ready in the event of warfare in return for the particular lands and stipends bestowed upon them. In 1635 he revised the Biike shohatto, a code of laws promulgated by Ieyasu that regulated the duties and functions of the daimyo and samurai, and established the system of sankin-kotai, which obliged the daimyo to reside part of the time in Edo and to leave their wives and children in Edo as hostages during the periods when they returned to their domains, thus insuring that they would not con¬template revolt. He prohibited the building of large ships and took other steps to tighten the control of the government over the feudal lords, decreeing that any infringement of the regulations should be subject to the severest penalties. In the same year, in order to prevent the spread of Christianity, he forbade Japanese to engage in foreign trade or to leave the country.
In 1637-38, when a revolt broke out among the Christians of the Shima- bara Peninsula of Kyushu in opposition to the oppressive rule of the Matsu- kura clan, he dispatched a large army to the area and in time succeeded in stamping out all resistance. From this time on he took increasingly stem measures against Christianity, in 1639 prohibited Portuguese ships from coming to Japan, and in time succeeded in closing off the country entirely from the outside world, the only exception being the highly restricted and government supervised trade that took place through the port of Nagasaki. This system of national seclusion remained in effect until the arrival of American warships in 1853 forced the opening of the country. Thus Iemitsu brought to final form the system of feudal rule initiated by his grandfather Ieyasu.
