Siege of Osaka (1614-1615): The Fall of the Toyotomi Clan

The Siege of Osaka was a pair of campaigns in 1614 and 1615 in which Tokugawa Ieyasu attacked Osaka Castle, the stronghold of Toyotomi Hideyori, son of the former ruler Toyotomi Hideyoshi. After a winter siege and a brief truce, a summer campaign ended with the burning of the castle and the deaths of Hideyori and his mother on 4 June 1615. The siege destroyed the last rival to the Tokugawa and closed the long era of civil wars in Japan.

Background

Toyotomi Hideyoshi unified Japan by 1590 and built Osaka Castle as his headquarters. When he died in 1598, his son Hideyori was only five years old. Tokugawa Ieyasu, the most powerful of the regents appointed to protect him, won the Battle of Sekigahara in 1600 and became shogun in 1603.

Hideyori was left with Osaka Castle and lands around it worth about 650,000 koku, a fraction of his father’s wealth but still substantial. He also had great prestige as Hideyoshi’s heir and a huge treasury. His mother, Yodo-dono, a niece of the warlord Oda Nobunaga, was a strong influence at his court. In 1603 Hideyori married Senhime, Ieyasu’s granddaughter, but tension between the two families remained.

By 1614 Ieyasu was in his seventies. He had handed the title of shogun to his son Hidetada, but he feared that after his death the Toyotomi could become a rallying point for discontented lords.

The bell incident

The pretext for war came from a temple bell. Hideyori had rebuilt the great Buddha hall of Hoko-ji in Kyoto, and in 1614 a large bronze bell was cast for it. The Tokugawa objected to its inscription. They claimed that the phrase kokka anko, “may the state be peaceful”, divided the two characters of Ieyasu’s name and so cursed him, and that another phrase wished prosperity to the Toyotomi.

Negotiations failed, and the Toyotomi began to prepare for war. They called on lords to join them, but none of the major daimyo did. Instead tens of thousands of ronin, masterless samurai who had lost their lords after Sekigahara, flocked to Osaka. Among them were capable commanders such as Sanada Yukimura, Goto Mototsugu and Chosokabe Morichika, and many Christian samurai.

The winter campaign

In November 1614 Ieyasu and Hidetada marched on Osaka with an army often estimated at around 190,000 men; fighting around the city began the following month. The defenders, perhaps 90,000 to 100,000 strong, relied on the great walls and moats of Hideyoshi’s castle.

The fiercest fighting came at the Sanada-maru, an earthwork fort that Sanada Yukimura had built to guard the weak southern side of the castle. In the twelfth month of the Japanese calendar, around the beginning of January 1615 by the Western calendar, Tokugawa troops attacked it and were driven back with heavy losses.

Unable to storm the castle, Ieyasu turned to bombardment with cannon, including European pieces obtained from Dutch and English traders, and to psychological pressure. Accounts say that a shot struck the castle near the quarters of Yodo-dono. In January 1615 the two sides agreed a peace. Under its terms the castle’s outer defences were to be removed. The Tokugawa filled in the outer moats and, by many accounts, went further than the Toyotomi side had understood, leaving the castle much weaker.

The summer campaign

When the Toyotomi began to restore their defences and gathered more ronin, Ieyasu declared war again in the spring of 1615. With its moats filled in, the castle could no longer withstand a long siege, so the Toyotomi commanders went out to meet the Tokugawa armies in the field.

On 2 June 1615 there were battles at Domyoji and at Yao and Wakae, south-east of Osaka. Goto Mototsugu was killed, and the Toyotomi forces fell back. The decisive clash, the Battle of Tennoji, was fought on 3 June south of the castle. Sanada Yukimura led a charge that, according to tradition, came close to Ieyasu’s own headquarters before it was beaten back. Yukimura was killed, and the Toyotomi army collapsed.

Fire spread through Osaka Castle. Senhime was escorted out to her grandfather’s camp, but pleas for her husband’s life were refused. On 4 June 1615 Hideyori and Yodo-dono took their own lives in a storehouse within the castle. Hideyori’s son Kunimatsu, aged about eight, was captured and executed in Kyoto, while his daughter was spared and became a Buddhist nun.

Key people

Tokugawa Ieyasu (1543–1616) directed both campaigns in person despite his age. He combined military pressure with negotiation, using the truce of early 1615 to weaken the castle’s defences before the final blow.

Toyotomi Hideyori (1593–1615) had grown up inside Osaka Castle and had little military experience. Contemporary accounts suggest that real decisions were often shaped by his mother and by senior retainers such as Ono Harunaga, and that the Toyotomi camp was divided between those who wanted to fight and those who hoped for compromise.

Yodo-dono (c. 1569–1615), born Chacha, was the eldest daughter of Oda Nobunaga’s sister Oichi. Her life was marked by the violent deaths of her family: her parents and stepfather all died in the wars of unification before she became Hideyoshi’s consort and Hideyori’s mother.

Sanada Yukimura (c. 1567–1615) came from a family that had sided against the Tokugawa at Sekigahara and had lived in exile on Mount Kudo. His defence of the Sanada-maru and his last charge at Tennoji made him the most celebrated warrior of the siege.

Consequences

The fall of Osaka ended the Toyotomi line and left the Tokugawa without a serious rival. Soon afterwards the era name was changed to Genna, and the peace that followed became known as the Genna Enbu, the “laying down of arms in Genna”. The Tokugawa shogunate used the moment to strengthen its control: in 1615 it issued the Laws for the Military Houses and an order limiting each domain to a single castle.

Ieyasu died less than a year later, on 1 June 1616, having secured his dynasty. Osaka Castle was rebuilt by the Tokugawa in the 1620s on top of Hideyoshi’s ruined fortress. The present keep is a modern reconstruction, completed in 1931.

Legacy

The siege became one of the best-known episodes in Japanese history. Sanada Yukimura, the brilliant commander who died fighting for a lost cause, became a popular hero in stories, plays and, later, novels, films and television dramas. A folding screen of the summer campaign, commissioned by the lord Kuroda Nagamasa, who fought on the Tokugawa side, shows the fighting and the suffering of civilians in vivid detail and is now an Important Cultural Property.

Timeline

• 1598, September: Toyotomi Hideyoshi dies, leaving his five-year-old son Hideyori.
• 1600, 21 October: Tokugawa Ieyasu wins the Battle of Sekigahara.
• 1614, summer: The dispute over the Hoko-ji bell inscription breaks out.
• 1614, November: Tokugawa armies march on Osaka; the winter campaign begins.
• 1614, December: Fighting begins around Osaka.
• 1615, early January: Tokugawa assaults on the Sanada-maru are repulsed.
• 1615, late January: Peace is agreed and the outer moats are filled in.
• 1615, 2 June: Battles of Domyoji and Yao-Wakae.
• 1615, 3 June: Battle of Tennoji; Sanada Yukimura is killed.
• 1615, 4 June: Hideyori and Yodo-dono die as Osaka Castle burns.

Why it matters

The Siege of Osaka was the last great battle of Japan’s age of civil wars. By destroying the Toyotomi, Tokugawa Ieyasu ensured that his family would rule Japan unchallenged, opening more than two centuries of peace under the shogunate.