Siege of Sawayama Castle

On the 15th day of the 9th month of Keichō 5 (1600), the Western Army collapsed at Sekigahara, and Ishida Mitsunari fled the field. Sawayama Castle, Mitsunari's home castle, became the Eastern Army's next target. Two days later, on the 17th day of the 9th month, a large Tokugawa force advanced on the castle town of Sawayama. The men defending the castle were Mitsunari's father, Ishida Masatsugu, and his elder brother, Ishida Masazumi. Alongside the battle of Sekigahara itself, this fall of the castle is still told today as an emblematic event that shows how fragile the Ishida house's glory was under the Toyotomi regime, which it had once dominated.

Ishida Mitsunari and the Road to Sekigahara

Ishida Mitsunari was a native of Ōmi Province. Discovered by Toyotomi Hideyoshi, he rose to prominence as a bugyō (administrator) and wielded considerable administrative skill in the practical work that supported the Toyotomi regime, including the Taikō land survey and the logistics of the Korean campaigns. He is regarded as the leading figure of the "civil-administration faction" (bunchi-ha), which valued administrative ability over martial achievement. After Hideyoshi's death, however, he grew alarmed at the arbitrary conduct of Tokugawa Ieyasu. In Keichō 5 (1600), he installed Mōri Terumoto as commander-in-chief and raised troops to topple Ieyasu. This uprising of the Western Army led to the Battle of Sekigahara. Mitsunari took de facto command of the Western Army himself and fought in the main battle on the 15th day of the 9th month. The battle initially seemed to favor the Western Army, but several hours after it began, Kobayakawa Hideaki, who had encamped on Mt. Matsuo, defected to the Eastern Army. Following him, Wakizaka Yasuharu, Ogawa Suketada, Kutsuki Mototsuna, and Akaza Naoyasu also defected to the Eastern side one after another. This mass defection broke the formation of the Western Army, and the main battle ended in a decisive Eastern victory in less than half a day.

For Tokugawa Ieyasu, to turn this victory into a secure foundation of power, it was essential to quickly seize the home bases of the Western Army's ringleaders and thoroughly remove any possibility of resistance. In particular, Mitsunari's home castle, Sawayama, was a symbolic target that showed the other daimyo what would become of those who showed defiance toward Ieyasu. It is believed that deploying Kobayakawa Hideaki and the other commanders who had defected during the main battle as the vanguard in the attack on Sawayama was also meant to have them demonstrate their loyalty to Ieyasu through action.

Sawayama Castle, the Home Base of Ishida Mitsunari

Sawayama Castle stood in Sakata District, Ōmi Province (present-day Hikone, Shiga Prefecture). It was an old castle built before the Nanboku-chō period, but in Tenshō 19 (1591), Ishida Mitsunari, an administrator of the Toyotomi regime, carried out a major renovation when he took up residence there and developed it as his home castle. Its grand layout centered on the Honmaru, with the Nishi-no-maru, Ni-no-maru, and San-no-maru arranged around it, and it was located at a key transport junction that controlled the Tōsandō road and Lake Biwa water transport. However, because Mitsunari's duties as administrator kept him in Fushimi for most of the time, it was actually his father, Masatsugu, who was entrusted with the castle. A contemporary satirical verse said, "Of Jibu-no-shō (Mitsunari's official title), there are two things beyond his worth: Shima Sakon and the castle at Sawayama." Its meaning was that the retainer and the castle were far more splendid than someone of Mitsunari's ability deserved. It is widely known as an anecdote that conveys both Mitsunari's power and the strength of Sawayama Castle. Mitsunari himself had gone to the Sekigahara main battle as the de facto leader of the Western Army, so only his father, Masatsugu, his elder brother, Masazumi, and other family members, along with a small force left behind to guard the castle, remained at Sawayama. Mitsunari's wife, Kōgetsu-in, also remained inside the castle.

News of the Defeat at Sekigahara and the Eastern Army's Advance South

When the Western Army was destroyed in the main battle on the 15th day of the 9th month, Tokugawa Ieyasu ordered his commanders to capture Sawayama Castle, the home base of the Ishida house. Kobayakawa Hideaki, Wakizaka Yasuharu, Kutsuki Mototsuna, Ogawa Suketada, and Akaza Naoyasu, all of whom had defected from the Western Army to the Eastern Army in the final stage of Sekigahara, were joined by Ii Naomasa, one of the Four Heavenly Kings of the Tokugawa, and Tanaka Yoshimasa, who, although a Toyotomi loyalist, had drawn close to Ieyasu early on. A total of roughly 15,000 troops advanced on Sawayama. The distance from the Sekigahara battlefield to Sawayama Castle was about one day's march, and the Eastern commanders, riding the momentum of their victory, changed course at once, leaving the castle's defenders almost no time to regroup. Inside Sawayama Castle, which had just received word of the defeat at Sekigahara, confusion was at its height, and almost no time remained to strengthen the defenses of the castle town. Most of the castle's troops had gone to Sekigahara, and the disparity in strength with the Eastern Army was overwhelming.

The Course of the Siege: A Two-Day Assault

On the morning of the 17th day of the 9th month, the Eastern Army surrounded Sawayama Castle and began a full-scale assault. The Kobayakawa and Wakizaka forces advanced toward the main gate side, and Tanaka Yoshimasa's force toward the rear gate side. Ishida Masatsugu directed the defense from the Honmaru, while Masazumi fought from the San-no-maru together with reinforcements sent from the Ōsaka forces. However, the garrison numbered only about 2,800, and it was utterly impossible for them to hold out against 15,000 Eastern troops for an extended period. The assault on the first day was repulsed through the gallant defense of the garrison. However, on the 18th day of the 9th month, Hasegawa Moritomo, who was inside the castle, secretly sided with the Eastern Army and guided the enemy in, and Sawayama Castle fell.

The Final Days of Ishida Masatsugu and Masazumi

When the castle fell, Ishida Masatsugu, Ishida Masazumi, Kōgetsu-in, Mitsunari's wife, and many other members of the clan took their own lives. The home base that Mitsunari had built at the height of his power fell after only two days of fighting, and the Ishida clan was nearly annihilated. The Ishida Gunki, a work from the Edo period, states that the castle was burned, but some have pointed out that the tiles scattered across the Honmaru and other areas show no signs of burning, suggesting that it was closer to a surrender of the castle than a fall by assault. Mitsunari himself was fleeing from Sekigahara. He was eventually captured and was executed at Rokujō-gawara in Kyoto on the 1st day of the 10th month of the same year (Keichō 5, 1600). While his father and elder brother perished together with the castle, Mitsunari alone survived as a defeated commander and was later executed, and this sequence of events has been passed down as an anecdote symbolizing the tragedy of the Ishida house.

Sawayama After the Fall and Its Legacy to the Present

After the fall, Sawayama Castle was taken over by Tokugawa forces, and in the following year, Ii Naomasa entered it as its lord. Naomasa planned to move to a new castle, disliking among other things that Sawayama had been Mitsunari's home castle, but he died in Keichō 7 (1602) before he could begin the project. Under his heir, Ii Naotsugu, construction of Hikone Castle began on Mt. Hikone in Keichō 8 (1603), and when Naotsugu moved to Hikone Castle in Keichō 11 (1606), Sawayama Castle was abandoned. There is also a tradition that building materials and part of the stone walls of Sawayama Castle were reused in the construction of Hikone Castle, so it can be said that the memory of Sawayama Castle was carried on in the land of Hikone in a different form. Today, only a few stone walls and parts of the enclosures remain at the Sawayama Castle site, which is known as a historic battlefield linked to the tragic end of Mitsunari. The castle site is owned by Ryōtan-ji at its western foot, and the trailhead lies within its precincts. The brave defense and final days of Ishida Masatsugu and Masazumi are still passed down locally today. The fall of Sawayama Castle is told as one episode in a series of events that marked the end of the Toyotomi regime and the arrival of the Tokugawa era, together with the Tanabe Castle and Ōtsu Castle sieges of the same period, which are often discussed alongside the main battle of Sekigahara.