Azuchi Castle

Timeline

1. 1576

   Construction begins

   In the first month of Tenshō 4, Oda Nobunaga named Niwa Nagahide chief construction commissioner and broke ground on Mount Azuchi, with Anō-shū stonemasons handling the stone walls.

2. May 1579

   Keep completed and Nobunaga enters

   The five-story keep was completed and Nobunaga moved in. Later that year he hosted the Azuchi Religious Debate between Jōdo-shū and Nichiren-shū factions inside the castle.

3. May 1582

   Reception of Tokugawa Ieyasu

   On the fifteenth of the fifth month of Tenshō 10, Akechi Mitsuhide served as host for the formal reception of Tokugawa Ieyasu at Azuchi — later read as a prelude to his break with Nobunaga.

4. June 1582

   Honnō-ji Incident and the great fire

   On the second day Akechi Mitsuhide's revolt forced Nobunaga's suicide at Honnō-ji in Kyoto; soon after Mitsuhide's defeat at Yamazaki around the fifteenth, the keep and inner bailey burned down.

5. 1585

   Abandoned with Hachimanyama Castle

   In Tenshō 13, with Toyotomi Hidetsugu's construction of Hachimanyama Castle nearby, Azuchi Castle was abandoned outright and the still-functional second bailey lost its remaining role.

6. 1918

   Azuchi Preservation Society founded

   In Taishō 7, local citizens formed the Azuchi Preservation Society (Azuchi Hoshōkai) to safeguard the castle site, launching the modern conservation movement.

7. 1926

   Designated national historic site

   In Taishō 15, the site was designated a national historic site under the Law for the Preservation of Historic Sites, Places of Scenic Beauty, and Natural Monuments, entering public protection.

8. 1952

   Promoted to Special Historic Site

   In Shōwa 27, the Cultural Properties Protection Law elevated the site to Special Historic Site — the highest tier of designation available to a Japanese castle ruin.

9. 1989-2009

   Twenty-year survey program

   From Heisei 1, Shiga Prefecture's twenty-year excavation and maintenance program steadily revealed the Ōte-michi, the traditional Hashiba Hideyoshi residence site, and other features.

10. 1992

    Partial keep reconstruction abroad

    Based on the Tenshu Sashizu plan, a reconstruction of the keep's fifth and sixth floors was shown at the Seville World Expo, and is now displayed at the Azuchi Castle Tenshu Nobunaga no Yakata museum.

11. 1999

    Seiryōden-style inner palace identified

    In Heisei 11, a building with the same plan as the Imperial Seiryōden was identified from foundation stones at the inner bailey, strengthening the imperial-visit theory.

12. 2006

    Selected as a Top 100 Castle

    On 6 April of Heisei 18, the Japan Castle Foundation selected Azuchi Castle as No. 51 of the Top 100 Japanese Castles.

13. 2024

    Inner-bailey approach platform measured

    In December of Reiwa 6, the Reiwa Great Survey reported that the building on the inner-bailey approach platform east of the tenshu-dai measured roughly 9.5 m by 17.5 m.

Detailed History

Azuchi Castle was built from 1576 to 1579 on Mount Azuchi on the eastern shore of Lake Biwa in Ōmi Province as one of the primary castles of Oda Nobunaga; Niwa Nagahide had responsibility for the construction. Nobunaga sited it close enough to Kyoto to watch over the approaches to the capital while keeping it outside the city, immune to its fires and conflicts, and at the same time strategically advantageous for managing the routes between his greatest rivals — the Uesugi to the north, the Takeda to the east, and the Mōri to the west. The complex was no mere military structure but a mansion intended to impress and intimidate rivals with both its defences and its lavish apartments, decoration, flourishing town and religious life. Its keep, called tenshu (or tenshukaku), was a seven-storey building with six floors above ground and one below — the beginning of the full-fledged tenshu tradition in Japanese castles — with audience halls, private chambers, offices and a treasury arranged as though it were a royal palace; all seven storeys were decorated by Kanō Eitoku, and the keep alone was unique in that its uppermost storey was octagonal and its façade colourfully painted with tigers and dragons rather than left solid white or black. Nobunaga built a defended castle town at the lake shore — including the Jōdo-shū temple Jōgon-in — and in summer 1577 issued a municipal charter granting residents tax and corvée immunities and forcing travellers on the Nakasendō to lodge there overnight, so that by 1582 its inhabitants numbered roughly 5,000. The castle hosted Tokugawa Ieyasu and other powerful guests, and the 1579 Azuchi religious debate between Nichiren and Jōdo-shū leaders took place there. In 1582 Akechi Mitsuhide's forces took the castle a few days after assassinating Nobunaga at Honnō-ji, and it was set aflame about a week later — accounts variously blame looting townspeople or one of Nobunaga's sons. Today only the stonework remains; the site was designated a National Historic Site in 1926 and upgraded to a Special National Historic Site in 1952, and in 2006 it was listed as one of Japan's Top 100 Castles by the Japan Castle Foundation.

Cultural Significance

Azuchi Castle was designated a National Historic Site in 1926 and elevated to a Special National Historic Site in 1952, and in 2006 was listed as one of Japan's Top 100 Castles by the Japan Castle Foundation. The site sits within the grounds of the Biwako Quasi-National Park, so that the surrounding lake landscape and the castle remains are protected together. The principal cultural significance of Azuchi is that, in the words of many researchers, it was the catalyst for the establishment of early modern castles in Japan from the Azuchi–Momoyama period onwards: the yamajiro of the Sengoku period had essentially been earthen fortresses cut into the mountain with rocks and earth heaped up for military priority, but Nobunaga's stone castle was a revolutionary departure from these — a 'show castle' built first on stone walls, with a tower keep at its heart, where political function stood beside the military one. Built not as a cold military structure but as a mansion meant to impress and intimidate rivals with lavish apartments and decoration alongside its defences, and the seat of his Tenka Fubu policy of unification by force, the castle gave its name to the Azuchi–Momoyama period itself. Its memory was further amplified abroad by the Azuchi Screens — six-folding panels depicting the castle and its town, gifted by Nobunaga to Pope Gregory XIII and displayed at the Vatican before vanishing — long considered pivotal works in the development of Japanese folding-screen painting.

Architectural Details

Azuchi is a textbook yamajiro mountain castle running from the summit of Mount Azuchi (which rises about 100 m above Lake Biwa) down its slopes, distinguished by its predominant use of stone — walls of huge granite blocks fitted carefully together without mortar, ranging from 5.5 to 6.5 m in thickness. At its core stood the great keep: the builder's plans for the castle show the donjon to be roughly 40 m tall with seven levels — a seven-storey building with six floors above ground and one below, the first true tower keep in Japan, with audience halls, private chambers, offices and a treasury arranged as though it were a royal palace and every storey decorated by Kanō Eitoku. The uppermost storey was octagonal, and the donjon's façade — unlike the solid white or black of other keeps — was painted with tigers and dragons. Around it Azuchi shows five other militarily distinct features: the predominant use of stone for the walls; the high central tower that gave defenders increased visibility for the use of guns; the massive thickness of the walls; and irregularly formed inner citadels that gave ample defensive positions against intruders. The castle was strategically placed at the intersection of three highways converging on Kyoto from the east, with the site rising 100 m above Lake Biwa. Confucius and other Confucian figures were depicted in the keep's paintings, suggesting Nobunaga's thinking was shifting from battlefield tactics toward the responsibility of ruling and ensuring peace and order.