The Wound from Pursuing Shimazu: The Sekigahara Wound That Delayed Naomasa's Death by Two Years

The Battle of Sekigahara on September 15, 1600 (Keichō 5, the fifteenth of the ninth month) was decided in about half a day with the victory of the eastern army of Tokugawa Ieyasu.

But in the closing phase of this combat, an unforeseen event occurred. Shimazu Yoshihiro's force from Satsuma, which had broken through the eastern encirclement, attempted to push out through the very middle of the battlefield in the reverse direction toward Ise.

This central breakthrough of the Shimazu is a rare tactical action in Sengoku-period battle history, and among the eastern commanders who pursued, Ii Naomasa too took a gunshot wound in the thigh — which would bring about his death two years later.

Shimazu Yoshihiro had taken the field with the Western Army but, from confusion of the chain of command during the combat, did not take full combat action.

In the afternoon, when the eastern victory had become certain, Yoshihiro adopted the 'Sutegamari' tactic of pushing out through the eastern center with a small force of about a thousand.

It was a tactic of leaving a fixed number of troops behind as a rear-guard buying time while the main body escaped, and Yoshihiro himself succeeded in returning to Satsuma by way of Ise.

The eastern commanders, taken by surprise, suddenly turned to pursue the fleeing Shimazu.

Ii Naomasa, as the eastern vanguard, had been involved in the principal scenes of the combat from the opening charge, and joined the pursuit of the Shimazu in the closing phase.

In the pursuit, the Shimazu rear-guard gun unit fired in counterattack, and Naomasa took a bullet in the thigh.

The horse of Honda Tadakatsu, who joined the same pursuit, is recorded as also having been brought down by gunfire.

Naomasa's wound, although accompanied by bleeding and pain, was not seen by contemporary judgment as fatal, and Naomasa himself attended the meritorious-service awards after the battle.

In the meritorious-service awards after Sekigahara, Naomasa was granted Ōmi Sawayama at 180,000 koku.

Sawayama was the former territory of Ishida Mitsunari of the Western Army, located at the strategic point of Kyoto, Ōmi, and the kinai.

The disposition of Naomasa was at the upper end among the Four Heavenly Kings, showing the thickness of Ieyasu's trust.

Naomasa entered Sawayama and began the management of the new territory, but the course of the gunshot wound was not encouraging.

Sengoku-period gunshot wounds, in an age without modern medicine, carried very high risk of infection.

Naomasa's wound did not fully heal and suppurated repeatedly. On February 1, 1602 (Keichō 7), about a year and a half after Sekigahara, Naomasa died at Sawayama Castle.

He was forty-two. The Sekigahara gunshot wound is taken as the direct cause of death.

As a case in which a single bullet closed the life of a warrior a year and a half later, it is recorded in Sengoku-period combat history.

Shimazu Yoshihiro's central breakthrough and the 'Sutegamari' tactic inflicted great damage on the eastern commanders.

It produced not only Naomasa's death, but also Honda Tadakatsu's wounding and many killed among the pursuing eastern commanders.

Yoshihiro himself returned to Satsuma, and the postwar Satsuma domain was maintained without reduction (a rare disposition for a Western Army-side house at Sekigahara).

Yoshihiro's tactical judgment continues to be a subject of military study even in the early modern period and afterward, cited in military textbooks as a typical case of escape from a desperate situation.

After Naomasa's death, the Ii house was inherited by his son Naokatsu, but on grounds of young age and ill health, in 1615 the headship passed to his younger brother Naotaka.

Naotaka moved the base from Sawayama to a new castle at Hikone and established the Hikone domain.

The foundation Naomasa built of the Ii house was inherited through the Edo period as the foremost of the fudai daimyō, and continued 250 years until the last great elder of the Tokugawa bakufu, Ii Naosuke (this site's id 27).

The single bullet taken at Sekigahara did not, in the long run, threaten the survival of the Ii house, and became the starting point of a house bearing the core of the Tokugawa bakufu.

At the Hikone Castle Museum, the armor Naomasa wore at Sekigahara is transmitted, and materials conveying the course of his wounding are exhibited.

In the Ii-family tradition, Naomasa is said to have devoted himself to the management of Ōmi while suffering the worsening of the gunshot wound.

The closing phase of Sekigahara, in which a single bullet brought about the death of a forty-two-year-old warrior, is remembered as a historical case showing the chance of fate in combat and the limits of battlefield medicine.