Battle of Takamatsu Castle in Bitchu

From the 4th to the 6th month of Tenshō 10 (1582), the Battle of Bitchū Takamatsu Castle was fought at Takamatsu Castle in Bitchū Province (present-day Takamatsu, Kita Ward, Okayama City). It is known for a large-scale "water siege" (mizuzeme) unlike any other in Japanese history. Hashiba Hideyoshi's unprecedented operation, in which he dammed the Ashimori River to submerge Takamatsu Castle, is still recounted as a masterpiece of engineering skill. Moreover, the battle unfolded at the same time as the Honnō-ji Incident (the 2nd day of the 6th month of Tenshō 10), and the irony of history gives it an even more dramatic hue.

The Terrain of Takamatsu Castle and the Mōri Defense Strategy

Bitchū Takamatsu Castle was a flatland castle (hirajiro) situated in the low-lying wetlands of the Okayama Plain. Surrounded by tributaries of the Ashimori River and by marshland, the castle, also called the "water castle," was extremely difficult to attack directly because of its terrain. Shimizu Muneharu, the defending commander on the Mōri side, held the castle with some 3,000 to 5,000 troops in this natural stronghold.

Shimizu Muneharu was a capable warrior and an important figure in the Mōri clan's control of Bitchū Province. His firm defense easily repelled even Hideyoshi's repeated attacks.

Hashiba Hideyoshi, looking at the terrain of Takamatsu Castle, arrived at a reversal of thinking: "If a castle is surrounded by water, then one need only surround it with more water." It was a plan to dam the Ashimori River with a massive embankment and turn Takamatsu Castle into a literal "island of water." With the advice of the military strategist Kuroda Kanbei as well, Hideyoshi decided on the unprecedented water-siege operation.

Miraculous Construction: The Water-Siege Embankment Completed in Twelve Days

On the 8th day of the 5th month of Tenshō 10 (1582), Hideyoshi's forces began building an embankment around Takamatsu Castle said to run roughly 4 km in total length. The work was large in scale and required vast amounts of manpower and materials. Hideyoshi mobilized farmers and craftsmen from the surrounding area, and the massive embankment is said to have been completed in just twelve days, by the 19th day of the 5th month.

The rainy season and the swelling of the Ashimori River coincided, and with the embankment completed, the area around Takamatsu Castle began to flood rapidly. The castle became an island floating in water, and the supply of food and materials from outside was completely cut off.

The Mōri clan sent a large army from the rear (forces led by three generals: Mōri Terumoto, Kikkawa Motoharu, and Kobayakawa Takakage), but on a flooded battlefield the advantage of numbers could not be brought to bear, and a stalemate persisted at the water's edge.

The Honnō-ji Incident: The Moment Historical Irony Converged

In the early morning of the 2nd day of the 6th month of Tenshō 10, at Honnō-ji in Kyoto, Oda Nobunaga took his own life after a rebellion led by Akechi Mitsuhide (the Honnō-ji Incident). News of this momentous event reached Hideyoshi, who was then conducting the siege of Bitchū Takamatsu Castle.

Hideyoshi, together with the military strategist Kuroda Kanbei, kept this information thoroughly secret. Without revealing any part of the Honnō-ji Incident to the Mōri side, he advanced peace negotiations with Mōri envoys and concluded a settlement on the condition that Shimizu Muneharu take his own life.

Shimizu Muneharu floated a boat on the waters around Takamatsu Castle, which had been submerged by heavy rain. There he performed a dance, composed his death poem, and took his own life. "Ukiyo o ima koso watare / mononofu no na o Takamatsu no koke ni nokoshite" ("Now at last I cross the floating world, leaving the name of a warrior on the moss of Takamatsu"). This death poem is praised by later generations as a masterpiece of the "warrior's final moment" of the Sengoku period.

The unusual end of performing seppuku on the water shows that the spirit of bushidō, taking one's own life with a blade, was upheld even on the extraordinary battlefield of a water siege. Shimizu Muneharu's spirit has been engraved forever in the history of bushidō.

Hideyoshi's "Chūgoku Ōgaeshi": On the Eve of the Curtain Falling on the Age of the Sword

After the settlement was concluded, Hideyoshi turned his army toward Kyoto at astonishing speed. This redeployment, known as the Chūgoku Ōgaeshi (the great march back from Chūgoku), was an unprecedented forced march covering more than 200 kilometers in little more than ten days. It was a feat that would have been impossible without Hideyoshi's leadership and his subordinates' loyalty.

Hideyoshi defeated Akechi Mitsuhide at the Battle of Yamazaki (July 2, 1582; Tenshō 10/6/13), establishing himself as Nobunaga's successor. The turbulent current of history, from the water siege of Bitchū Takamatsu Castle to the Battle of Yamazaki, was a turning point that moved the course of Japanese history.

Bitchū Takamatsu Castle from the Perspective of the Japanese Sword: A Decisive Battle Right in Front of Bizen Sword Country

The battle of Bitchū Takamatsu Castle took place in Bitchū Province (present-day western Okayama Prefecture), directly to the west of Bizen Province (present-day eastern Okayama Prefecture), Japan's greatest sword-producing region. Famous blades forged by the smiths of Bizen Osafune were widely circulated in this era among both the Hideyoshi and Mōri forces.

No clear record survives of the sword used in Shimizu Muneharu's seppuku, but as a warrior of Bitchū he very likely favored swords of the Bizen tradition. The scene of that single blade being wielded on a boat floating on the water is passed down as an unparalleled image, even in the history of swords.

Hachisuka Masakatsu, a senior retainer of Hideyoshi, also played an important role in strategy and negotiation in the battle of Bitchū Takamatsu Castle. As one of the battles embodying the last brilliance of the age of the sword, and as the eve of the upheaval of the realm marked by the Honnō-ji Incident and the Battle of Yamazaki, the battle of Bitchū Takamatsu Castle is an unforgettable presence in the history of Japanese swords.

Shimizu Muneharu's Death Poem and Seppuku on the Water: One of the Greatest Scenes in the History of Swords

"Ukiyo o ima koso watare / mononofu no na o Takamatsu no koke ni nokoshite." The scene in which Shimizu Muneharu composed this death poem and took his own life on a boat on the water is passed down to later generations as one of the most beautiful and tragic scenes in Japanese samurai literature.

In the unusual circumstances of a battlefield submerged in water, he sat on a boat as a platform, quietly performed a final dance, composed a death poem, and gripped a blade to cut his belly. This sequence of actions shows the ultimate expression of the role the sword played as "the final vessel of the warrior's soul." Muneharu's last moments, unfolding in the tranquil space on the water, away from the clamor of the battlefield, embodied the threefold symbolism of beauty, death, and pride that the Japanese sword carries.

It is said that soldiers and officers of both sides who witnessed this scene were deeply moved, and that Hideyoshi also praised Muneharu's loyalty. Showing respect toward the final moments of an enemy commander was also one aspect of bushidō in the age of the sword.

The Site of Bitchū Takamatsu Castle and Its Legacy

Today, in Takamatsu, Kita Ward, Okayama City, the ruins of Bitchū Takamatsu Castle are preserved as a historic site and have become a tourist destination as the site of the "water siege." Parts of the embankment Hideyoshi built have also been confirmed, and traces of the large-scale construction of that time remain to this day.

After the battle of Bitchū Takamatsu Castle, Hideyoshi reached Yamazaki through the Chūgoku Ōgaeshi and began his path to becoming the ruler of the realm. This series of events (the water siege, Shimizu Muneharu's seppuku, the Honnō-ji Incident, the Chūgoku Ōgaeshi, and the Battle of Yamazaki) was a historical miracle that occurred within just a few weeks, and it is passed down as the most dramatic chain of events in Japanese history. Bitchū Takamatsu Castle, located at the center of that dramatic history, is counted among the last great stages that graced the closing of the age of the Japanese sword.

Bizen Swords and Bitchū Takamatsu Castle: A Battlefield in Front of Japan's Greatest Sword-Producing Region

Takamatsu, where the battle of Bitchū Takamatsu Castle took place, lies on the border with Bizen Province (present-day eastern Okayama Prefecture) and is only a few dozen kilometers from the sword-smithing town of Bizen Osafune. At the time of Tenshō 10 (1582), many smiths of Sue-Bizen, led by Sukesada, were active in Bizen Osafune, and it is highly likely that soldiers and officers on both the Hideyoshi and Mōri sides wore works by these master smiths at their waists.

In the area around Takamatsu Castle, where the battlefield was submerged by the unprecedented tactic of a water siege, direct hand-to-hand combat was limited. Even so, swords and spears were still active in fighting on land. The sword used for Shimizu Muneharu's seppuku is thought to have been a practical blade forged by a master smith of Bizen or Bitchū, and that single blade was the "leading role" adorning one of the most moving scenes in the history of the Japanese sword.

The ruins of Bitchū Takamatsu Castle (present-day Takamatsu, Kita Ward, Okayama City) are still preserved as a historic site. Stone monuments remain that commemorate the site of the water-siege embankment and the location on the boat where Shimizu Muneharu took his own life. For those who love swords and history, this place is a special spot where one can feel with one's whole body "the era in which the sword shone for the last time."