Tokugawa Ieyasu (born Matsudaira Takechiyo; January 31, 1543 – June 1, 1616) was a Japanese samurai, daimyo and the founder and first shogun of the Tokugawa shogunate of Japan, which ruled from 1603 until the Meiji Restoration in 1868. He was the third of the three "Great Unifiers" of Japan, along with his former lord Oda Nobunaga and fellow Oda subordinate Toyotomi Hideyoshi. The son of a minor daimyo, Ieyasu once lived as a hostage under daimyo Imagawa Yoshimoto on behalf of his father. He later succeeded as daimyo after his father's death, serving as ally, vassal, and general of the Oda clan, and building up his strength under Oda Nobunaga.
After Oda Nobunaga's death, Ieyasu was briefly a rival of Toyotomi Hideyoshi, before declaring his allegiance to Toyotomi and fighting on his behalf. Under Toyotomi, Ieyasu was relocated to the Kanto plains in eastern Japan, away from the Toyotomi power base in Osaka. He built his castle in the fishing village of Edo (now Tokyo). He became the most powerful daimyo and the most senior officer under the Toyotomi regime. Ieyasu preserved his strength during Toyotomi's failed attempts to conquer Korea. After Hideyoshi's death and the Battle of Sekigahara, Ieyasu seized power in 1600.
He received appointment as shōgun in 1603, and voluntarily resigned from his position in 1605, although he still held the de facto control of government until his death in 1616. He implemented a set of careful rules known as the bakuhan system. This system used precisely graded rewards and punishments to encourage (or compel) the daimyo and samurai to live in peace with each other under the Tokugawa shogunate. Following his death, his successors shifted the government to Edo in 1638 and enacted the Sakoku policy of isolationism in 1639 which closed off Japan from the outside world for over 200 years until the Meiji era began in 1868.
Tokugawa Ieyasu was born in Okazaki Castle on the 26th day of the twelfth month of the eleventh year of Tenbun, according to the Japanese calendar, January 31, 1543 according to the Western calendar. Originally named Matsudaira Takechiyo (松平 竹千代), he was the son of Matsudaira Hirotada (松平 広忠), the daimyo of Mikawa of the Matsudaira clan, and Odai no Kata (於大の方; Lady Odai), the daughter of a neighbouring samurai lord, Mizuno Tadamasa (水野 忠政). His mother and father were step-siblings. They were 17 and 15 years old, respectively, when Takechiyo was born.
During the Muromachi period, the Matsudaira clan controlled a portion of Mikawa Province (the eastern half of modern Aichi Prefecture). Ieyasu's father, Matsudaira Hirotada, was a minor local warlord based at Okazaki Castle who controlled a portion of the Tōkaidō highway linking Kyoto with the eastern provinces. His territory was surrounded by stronger and predatory neighbors, including the Imagawa clan based in Suruga Province to the east and the Oda clan to the west. Hirotada's main enemy was Oda Nobuhide, the father of Oda Nobunaga.
In the year of Takechiyo's birth, the Matsudaira clan split. Hirotada's uncle, Matsudaira Nobutaka defected to the Oda clan. This gave Oda Nobuhide the confidence to attack Okazaki. Soon afterwards, Hirotada's father-in-law died, and his heir, Mizuno Nobumoto, revived the clan's traditional enmity against the Matsudaira and declared allegiance to Oda Nobuhide as well. As a result, Hirotada divorced Odai-no-kata and sent her back to her family. Hirotada later married different wives, and Takechiyo eventually had 11 half-brothers and sisters.
As Oda Nobuhide continued to attack Okazaki, Hirotada turned to his powerful eastern neighbor, Imagawa Yoshimoto, for assistance. Yoshimoto agreed to an alliance under the condition that Hirotada send his young heir to Sunpu Domain as a hostage. Oda Nobuhide learned of this arrangement and had Takechiyo abducted. Takechiyo was five years old at the time. Nobuhide threatened to execute Takechiyo unless his father severed all ties with the Imagawa clan. However, Hirotada refused, stating that sacrificing his own son would show his seriousness in his pact with the Imagawa. Despite this refusal, Nobuhide chose not to kill Takechiyo, but instead held him hostage for the next three years at the Honshōji Temple in Nagoya. It was rumored that Oda Nobunaga met Takechiyo at the temple, when Takechiyo was six years old, and Nobunaga was 14. However, Katsuhiro Taniguchi reported there is no concrete historical records about this story of first meeting between Takechiyo with Nobunaga.
In 1549, when Takechiyo was six, his father Hirotada died of unknown causes. There was a popular theory that he was murdered by his vassals, who had been bribed by the Oda clan. However, a scholarly article published by Muraoka Mikio in 2015 states that the assassination theory is unreliable and Hirotada's death may have been caused by a natural illness.
Around the same time, Oda Nobuhide died during an epidemic. Nobuhide's death dealt a heavy blow to the Oda clan.
In 1551, an army under the command of Imagawa Sessai laid siege to the castle where Oda Nobuhiro, Nobuhide's illegitimate eldest son, was living. Nobuhiro was trapped by the Imagawa clan but was saved through negotiation by Oda Nobunaga, Nobuhide's second son and heir. Sessai made an agreement with Nobunaga to take Takechiyo back to Imagawa, and he agreed. Takechiyo, now nine years old, was taken as a hostage to Sunpu.
At Sunpu, he was treated fairly well as a potentially useful ally of the Imagawa clan until 1556 when he was 14 years old. Yoshimoto decided that the Matsudaira clan's territory would be inherited by Takechiyo in the future, with the aim that the Imagawa clan could rule the area by extensions of their Matsudaira clan as their vassal, including Zuien-in (the daughter of Matsudaira Nobutada and Takechiyo's great-aunt), who was the only member of the Anjo Matsudaira clan left in Okazaki Castle.
In 1556, Takechiyo officially came of age, with Imagawa Yoshimoto presiding over his genpuku ceremony. Following tradition, he changed his name from Matsudaira Takechiyo to Matsudaira Jirōsaburō Motonobu (松平 次郎三郎 元信). He was also briefly allowed to visit Okazaki to pay his respects to the tomb of his father, and receive the homage of his nominal retainers, led by the karō Torii Tadayoshi.
One year later, at the age of 15 (according to East Asian age reckoning), he married his first wife, Lady Tsukiyama, a relative of Imagawa Yoshimoto, and changed his name again to Matsudaira Kurandonosuke Motoyasu (松平 蔵人佐 元康). A year later, their son, Matsudaira Nobuyasu, was born. He was then allowed to return to Mikawa Province. There, the Imagawa ordered him to fight against the Oda clan in a series of battles.
Motoyasu fought his first battle in 1558 at the siege of Terabe. The lord of Terabe, Suzuki Shigeteru (or Suzuki Shigetatsu), betrayed the Imagawa by defecting to Oda Nobunaga. This was nominally within Matsudaira territory, so Imagawa Yoshimoto entrusted the campaign to Motoyasu and his retainers from Okazaki. Motoyasu led the attack in person, but after taking the outer defences, he burned the main castle and withdrew. As anticipated, the Oda forces attacked his rear lines, but Motoyasu was prepared and drove off the Oda army.
He then succeeded in delivering supplies during the siege of Odaka Castle a year later. Odaka was one of five disputed frontier forts under attack by the Oda clan, and the only one that still remained under Imagawa control. Motoyasu launched diversionary attacks against the two neighboring forts and, when the garrisons of the other forts came to assist, Motoyasu's supply column was able to reach Odaka.
By 1559, the leadership of the Oda clan had passed to Oda Nobunaga. In 1560, Imagawa Yoshimoto, leading a large army of 25,000 men, invaded Oda territory. Motoyasu was assigned a separate mission to capture the stronghold of Marune in the Siege of Marune operation. As a result, he and his men were not present at the Battle of Okehazama where Yoshimoto was killed in a surprise assault by Nobunaga, In the end, Motoyasu managed to capture Marune castle.