The Siege of Shiga—Nobunaga's Greatest Ordeal and Swords Bearing Witness to the Tensions of Mt. Hiei

The Siege of Shiga (Shiga no jin) was a prolonged standoff conducted from September to December 1570 (the first year of Genki) in Shiga, Ōmi Province (present-day northern Ōtsu, Shiga Prefecture). With the combined forces of Asai Nagamasa and Asakura Yoshikage and the warrior monks (sōhei) of Enryaku-ji on Mt. Hiei coordinating their efforts to strike Nobunaga from north and south, this battle is counted among the most harrowing of Nobunaga's lifetime. Ultimately, Nobunaga was compelled to accept a truce brokered by the imperial court and the Ashikaga shogunate, yet this humiliation became the direct catalyst for the burning of Mt. Hiei in the following year, Genki 2 (1571).

Background—Alliance Collapse and Encirclement

In April of Genki 1, Nobunaga, believing his ally Asai Nagamasa would never betray him for reasons of old allegiance, invaded northern Ōmi with the aim of eliminating Asakura Yoshikage (the Battle of Kanegasaki). News of Asai Nagamasa's sudden defection struck Nobunaga's encampment like a thunderbolt, and Nobunaga beat a hasty retreat (the so-called "withdrawal from Kanegasaki"). In the subsequent Battle of Anegawa in June, the Nobunaga-Tokugawa allied army defeated the Asai-Asakura alliance, but fell short of capturing their home bases.

By September, the combined Asai-Asakura forces moved south along the western shore of Lake Biwa and advanced into Shiga District (present-day northern Ōtsu). Nobunaga suffered significant losses, including the death in battle on September 20 of Mori Yoshinari, who held Usayama Castle for the Oda. Moreover, Enryaku-ji on Mt. Hiei lent its support to the Asai-Asakura faction, providing surveillance and aid from above, forcing Nobunaga into a disadvantageous position hemmed in on both sides by Mt. Hiei.

The Rugged Terrain of Shiga and the Tensions Swords Reveal

The western shore of Lake Biwa, where the Siege of Shiga unfolded, was a narrow space squeezed between the steep slopes of Mt. Hiei and the water—ill-suited for deploying large armies. This geographic constraint created conditions in which swords and spears in close combat became decisive, more so than long-range bows and firearms.

The swords borne by the ashigaru footsoldiers and commanders assembled from various regions naturally showed considerable diversity in their origins. Nobunaga's forces favored blades from Mino and Owari smiths—Seki-mono and Owari-mono—while the Asai-Asakura side likely relied upon swords from Echizen and Ōmi. Though the Siege of Shiga ultimately concluded through truce rather than large-scale pitched combat, during the three-month standoff both armies' blades remained in a constant state of tension, with scouts and skirmishes playing out daily.

Nobunaga's Plight and the Imperial Court and Yoshiaki's Intervention

Hemmed in on both sides at the Siege of Shiga and further pressed by the uprising of the Hongan-ji (the Genki Ikkō Uprising), Nobunaga found himself forced to respond on multiple fronts. With the stalemate continuing into November, Nobunaga took the extraordinary step for him of seeking mediation from the imperial court and the shogun Ashikaga Yoshiaki—an unusual "compromise" for Nobunaga.

On December 13, through the mediation of the imperial court and Yoshiaki, a truce was established. Nobunaga acceded to certain terms regarding the Asai and Asakura, and both armies withdrew. Whether Nobunaga accepted the truce to avoid prolonged attrition in the winter mountains or to prioritize dealing with Hongan-ji and the Takeda, it remained one of the rare instances in Nobunaga's career when he himself sought compromise.

The Resolve for the Burning of Mt. Hiei

At the Siege of Shiga, Nobunaga's fury ran deep at the sight of Enryaku-ji's monks and clerics harboring the Asai-Asakura faction and wielding religious authority for political ends. After the truce was established, Nobunaga bided his time, and on September 12 of the following year, Genki 2 (1571), he suddenly sent a large army against Enryaku-ji on Mt. Hiei, burning down the temple halls and pagodas, including the Konponchūdō, and slaughtering great numbers of monks, clerics, and lay followers indiscriminately (the Burning of Mt. Hiei).

Many historians point out that the direct cause of this "unprecedented outrage" (according to contemporary records) lay in Enryaku-ji's political stance during the Siege of Shiga. For Nobunaga, Enryaku-ji represented "political power masquerading under the guise of religion," and his memory of its armed forces causing suffering to his troops with swords, naginata, and stone bows remained vivid.

Impact on Sword Culture—the Union of Weapon and Sacred Object Consumed by Fire

In the burning of Enryaku-ji, numerous weapons and swords stored within the temple were also lost to the flames. The sōhei (warrior monks) of Enryaku-ji, known as dōshū, wielded naginata as their primary weapon and bore swords and spears while clad in armor—as "armed religious practitioners," they wielded considerable political influence throughout the Muromachi period. The Siege of Shiga, as the final battle in which Enryaku-ji's martial power caused Nobunaga suffering, symbolizes the twilight of the age of armed monasticism.

After Nobunaga's control of Mt. Hiei, the traditional "armed temple-shrine complexes" underwent significant decline, and the primary holders of swords increasingly converged upon the warrior class. The series of events surrounding the Siege of Shiga and the burning of Mt. Hiei can be positioned as a historical episode that redefined who the "bearers" of swords would be in the waning Sengoku period.