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Shiga · Nagahama

Odani Castle

小谷城

Nagahama, Shiga

CastleMountain castle (yamajiro)Japan's 100 Fine Castles No. 52

What makes this castle distinctive

The mountaintop castle where Azai Nagamasa lived with Oichi and their three daughters, and where he took his own life when Nobunaga attacked.

Why?

Odani was the seat of three generations of the Azai family, who ruled northern Omi (Shiga). Azai Nagamasa married Oichi, the sister of Oda Nobunaga, but later turned against him; in 1573 the castle fell and Nagamasa died by his own hand in the Akao residence inside the castle. It is also known as the childhood home of their daughters Chacha, Hatsu and Go, the Azai sisters.^[3][4][7]

Three things not to miss

The Senjojiki, a broad leveled bailey on the mountaintop, July 2008. It is a large part of the main enclosure where the castle's central buildings are thought to have stood.

The Senjojiki in the main enclosure, and its surviving stone walls

Where: The honmaru (main enclosure) site, about 30 minutes' climb from the Bansho site, plus the Kurogane Gomon gate site and Ohiroma site on the way.
What to look at: The Senjojiki, said to be the largest leveled bailey (kuruwa) in the castle, stone walls among the trees, and the stone steps at the Kurogane Gomon gate site.
Why it's interesting: The national heritage description notes that stone walls still remain at the main enclosure, Naka-no-maru, Sannomaru and the Akao residence. Finding stonework at a Warring States-era mountain castle, before stone-walled castles became common, is a highlight. Excavations suggest the Ohiroma area was where the Azai family held government business and ceremonies.^[2][3][4]
Can you see it?: Visible from outsideReached on foot by mountain trail. The path beyond the main enclosure becomes rough.

Where Azai Nagamasa died (Akao residence site)

Where: Next to the Kyogokumaru, at the residence site of the senior retainer Akao Kiyotsuna.
What to look at: The stone marker for the place where Nagamasa took his own life.
Why it's interesting: In 1573, under attack by Nobunaga's army, Nagamasa is said to have taken his life here. Oichi and her three daughters were brought out of the castle alive, and each daughter went on to play a part in history. The spot marks the end of the Azai family.^[4][7]
Can you see it?: Visible from outsideReachable by trail near the main enclosure.

The view over northern Shiga and Lake Biwa

Where: Near the Bansho site and from the baileys on the mountain.
What to look at: The plain below, the direction of the Ane River, and Lake Biwa with Chikubushima in the distance.
Why it's interesting: Odani controlled the Hokuriku and Nakasendo roads and was close to Lake Biwa. The national heritage description says it overlooks the Ane River far below and guarded the whole northern lake area. The view shows why the Azai chose this mountain.^[2][3]
Can you see it?: Visible from outsideVisible in clear weather.

At a glance for visitors

Nearest station: 30 min walk from JR Kawake Station
Climb: Steep climb
Time neededEditors' estimate: 2.5-3 hours round trip from the foot to the main enclosure; allow half a day including the museum.
Admission: 350 yen high school age and up, 150 yen elementary/junior high, free for younger children (groups of 20+: 300 / 130 yen).
Hours: 9:00-17:00 (last entry 16:30)
Access: Open to visitors
The castle site is free and open to walk. Visitors are asked not to drive the forest road when there is snow, and rental bicycles are not allowed on it. The Japan 100 Castles stamp is at the Odani Castle Sengoku History Museum (check the museum's notices for closed days).

Checked: 2026-10-03

View on map Open in Google Maps Odani Castle Sengoku History Museum Odani Castle ruins (Nagahama-Maibara tourism association)

The story of this castle

Historical record

A mountain commanding two highways

Odani Castle was built along the ridges running south from Mt. Odani, about 495 m high. It controlled key points on the Hokuriku and Nakasendo highways and lay close to Lake Biwa. Its baileys were strung along the ridges from the summit, making the whole mountain part of the castle.^[3][4]

Historical record

Built by Azai Sukemasa, home to three generations

Azai Sukemasa is thought to have built the castle by around 1525 (accounts of the exact year differ). Three generations, Sukemasa, Hisamasa and Nagamasa, ruled northern Omi from here.^[8][7]

Historical record

Alliance with Nobunaga, then war

The third lord, Nagamasa, married Nobunaga's sister Oichi and allied with the Oda, but later sided with the Asakura family against Nobunaga. Even after the Battle of Anegawa in 1570, Nobunaga could not quickly take the strong castle at Odani.^[4][7]

Historical record

The fall in 1573, and abandonment

In 1573 Nobunaga's army attacked and the Azai family was destroyed; Nagamasa is said to have died in the Akao residence. The castle was given to Hashiba (later Toyotomi) Hideyoshi, but he built Nagahama Castle on the lakeshore at Imahama (today's Nagahama) and moved there, so Odani was abandoned.^[2][4]

Historical record

Remains on the mountain, a National Historic Site

The buildings are gone, but baileys, dry moats and stone walls remain across the mountain, and the site became a National Historic Site in 1937. The Odani Castle Sengoku History Museum at the foot of the mountain shows portraits linked to the three Azai lords and Oichi, finds from the castle site, and old maps of the castle.^[1][2][4]

People of this castle

Third lord, who fought Nobunaga and died at the castle

Azai Nagamasa

浅井長政

1545–1573

Third lord of the Azai family of northern Omi. He married Oda Nobunaga's sister Oichi but later fought Nobunaga alongside the Asakura and was destroyed at Odani Castle.

Nagamasa's wife and Nobunaga's sister; mother of the three Azai sisters

Oichi

お市の方

?–1583

Oda Nobunaga's sister and the wife of Azai Nagamasa. She raised her three daughters, Chacha, Hatsu and Go, at Odani Castle.

Lord

Toyotomi Hideyoshi

豊臣秀吉

1537–1598

The warlord who carried on Oda Nobunaga's work and unified Japan. In 1583 he began building Osaka Castle on the site of the Osaka Hongan-ji temple.

Built

Azai Sukemasa

浅井亮政

1491–1542

Lord

Azai clan

浅井氏

Timeline

1525
Thought to have been built by this year; accounts differ
Azai Sukemasa builds Odani Castle^[8][7]
1570
Battle of Anegawa: the Azai and Asakura lose to the Oda and Tokugawa^[7]
1573
The castle falls to Nobunaga and the Azai family is destroyed^[2][7]
1575
Hideyoshi moves to Nagahama Castle; Odani is abandoned^[4][7]
1937
Designated a National Historic Site^[2][4]

Buildings and remains

The keep today

No keep was built

A Warring States-era mountain castle; the Japan Castle Foundation lists no keep. A main building is thought to have stood in the main enclosure, but no keep has been confirmed.

The site today

Baileys, dry moats and stone walls survive in the forest on Mt. Odani. Hiking trails lead up, and the Odani Castle Sengoku History Museum and the Sengoku Guide Station are at the foot.

Main buildings

Site only

Main enclosure site (Senjojiki)

Said to be the largest bailey; stone walls remain.^[2][4]

Site only

Kurogane Gomon gate site and Ohiroma site

The gate into the main enclosure and the bailey thought to be the Azai government hall.^[4]

Site only

Akao residence site

Said to be where Nagamasa died.^[4]

Site only

Sannomaru and Ozuku

Baileys beyond the main enclosure and the summit area; rough trail.^[2][3]

Key facts

Type: Castle
Setting: Mountain castle (yamajiro)built on a mountain; expect a climbEditorial article
Period: Medieval (c.1185–1570s)Editorial article
Keep (tenshu): No keep was builtthe castle never had a keepEditorial article
Built by: Azai SukemasaJapan Castle Foundation
Built: 1525Japan Castle Foundation
Main lords: Toyotomi Hideyoshi, Azai clanJapan Castle Foundation
Abandoned: 1575Wikipedia (ja)
Remains to see: Baileys / enclosures (kuruwa), Trench cuts (horikiri), Earthen ramparts, Stone walls, Vertical moats (tatebori), Fortified gateways (koguchi), MoatsEditorial article
Designation: National Historic Site (Odani Castle ruins) (1937)Editorial article
Selection: Japan's 100 Fine Castles No. 52Japan Castle Foundation

Visiting

Access

Open to visitors

The castle site is free and open to walk. Visitors are asked not to drive the forest road when there is snow, and rental bicycles are not allowed on it. The Japan 100 Castles stamp is at the Odani Castle Sengoku History Museum (check the museum's notices for closed days).

Address

Odani-Gujo-cho and Kohoku-cho Ibe, Nagahama, Shiga (museum: 139 Odani-Gujo-cho, Nagahama 529-0312)^[1][3]

Checked: 2026-10-03

Nearest stations and how to get there

JR Kawake StationJR Hokuriku Line

about 30 min walk · Steep climb

About 30 minutes' walk (2.2 km) or 15 minutes by rental bicycle to the museum. From the Sengoku Guide Station at the foot it is about 40 minutes up to the Bansho site and another 30 minutes to the main enclosure.^[1][3]

Checked: 2026-10-03

Hours and admission

Odani Castle Sengoku History Museum

Hours: 9:00-17:00 (last entry 16:30)
Closed: Tuesdays (the next day if Tuesday is a holiday), December 28 - January 4, plus closures for exhibit changes or weather warnings.
Admission: 350 yen high school age and up, 150 yen elementary/junior high, free for younger children (groups of 20+: 300 / 130 yen).^[1][4]

Checked: 2026-10-03

By car / parking

From the Odanijo Smart IC on the Hokuriku Expressway; turn toward the mountain at the Gujo-minami light on Route 365 to reach the museum. The narrow Odani forest road leads up to the Bansho site, but it is closed to private cars while the shuttle bus runs.^[1][5]

Checked: 2026-10-03

Grounds opening hours

Open all day, free (per the tourism association).^[3]Checked: 2026-10-03

Time neededEditors' estimate

2.5-3 hours round trip from the foot to the main enclosure; allow half a day including the museum.

Steps, slopes and footing

A real mountain hike: about 40 minutes from the Guide Station to the Bansho site, 30 minutes on to the main enclosure, 20 minutes to Sannomaru, and 60 minutes to Ozuku (each one way). Beyond the main enclosure the trail is rough; proper hiking gear is needed. Expect snow and ice in winter.^[3]

Wheelchairs and strollers

Not practical by wheelchair. On shuttle-bus days you can ride up to the Bansho site.^[5]Checked: 2026-10-03

Toilets and rest

Toilets at the museum. Not confirmed on the mountain.^[1][6]

English signs / audio guide

No English information was found.

Seasons

Cherry blossoms in spring, fresh green in early summer, autumn leaves in fall. In 2026 a shuttle bus runs from the foot to the Bansho site on weekends and holidays from November 14 to 23, with local storyteller guides at key points.^[3][5]

Photography

The museum asks visitors not to take photos or video inside.^[1]

Works, closures and restrictions

On Sunday, October 4, 2026, the museum is closed for the Odani Castle Sengoku Festival (toilets only open), with traffic restrictions and no access to the museum parking. Bookings for the museum's castle guides are currently suspended.^[6]Checked: 2026-10-03

Editors' guide

An editorial guide based on sources and confirmed information — not a first-hand visit report.

Who will enjoy it

For fans of the story of Azai Nagamasa, Oichi and the three Azai sisters, and for hikers who want to explore a Warring States mountain castle.

What makes it interesting

Climb from the Bansho site past the Kurogane Gomon gate and the Ohiroma to the Senjojiki in the main enclosure to feel the approach to the heart of the castle. Don't miss the Akao residence marker and the view over northern Shiga.

Before you go

The site is a real mountain trail, rougher beyond the main enclosure, and the foot is a 30-minute walk from the station. The museum closes on Tuesdays, and on October 4 for the festival.

Ways to enjoy it

Visit the museum first to see the Azai family history and old maps, then climb so you can picture what stood where. On autumn shuttle-bus days you can ride halfway up.

Photos

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Open questions

Accounts of when the castle was built differ, including 1516 and 1523-24.
The national heritage text dates Nobunaga's attack to 1572, but the fall of the castle and the end of the Azai family are generally dated 1573.
Nagamasa's death at the Akao residence and where Oichi and the daughters lived include elements of tradition.
Toilets on the mountain, English information and the dates of any winter road closure could not be confirmed.