CastleHilltop castle (hirayamajiro)Next 100 Fine Castles No. 164
What makes this castle distinctive
Two stone walls run straight down the mountainside, linking the castle on the summit with the castle at its foot.
Why?
Sumoto Castle consists of an upper castle on top of Mt. Mikuma and a lower castle at its foot. On the north slope between them, two "climbing stone walls" (nobori-ishigaki) still connect the two. Only a handful exist anywhere in Japan, and they are thought to be linked to the castles Japanese forces built in Korea during Toyotomi Hideyoshi's invasions in the 1590s.[1][2][3]
Three things not to miss
01
The climbing stone walls linking upper and lower castles
Where
The north slope of Mt. Mikuma, in two places (east and west).
What to look at
Lines of stone wall running straight down the slope.
Why it's interesting
Stone walls usually ring a bailey, but climbing walls run vertically down a slope to stop attackers moving sideways across it. The Hyogo Prefectural Museum of History lists Sumoto alongside Matsuyama (Iyo) and Hikone as one of the few examples. The well-preserved walls linking the upper and lower castles are one reason Sumoto was chosen for the Continued Top 100 Japanese Castles.[1][2][3]
Can you see it?
Partly visibleThey lie on the mountainside; the best route and viewpoints are not confirmed.
The mock keep on the keep base, and the view over Osaka Bay
Where
The keep base (tenshudai) at the highest, northern end of the main enclosure.
What to look at
The small mock keep on its stone base, and the view down to Sumoto, Ohama Beach and Osaka Bay.
Why it's interesting
It is not a reconstruction of any historical keep. It is a reinforced-concrete "castle-shaped rest house," begun in 1928 to mark the enthronement ceremonies of Emperor Showa and finished in 1929. Sumoto City describes it as Japan's oldest mock keep. The view from the keep base is one of the Eight Views of Sumoto.[1][3][5][6]
Can you see it?
Partly visibleThe exterior and the view from the keep base are open to all. The building itself is closed because of its age.
The Great Stone Stairway and walls of stone everywhere
Where
The Great Stone Stairway on the south side of the main enclosure, and the baileys around it.
What to look at
The broad stairway between stone walls, and wall corners where long stones are stacked in alternating directions.
Why it's interesting
Every bailey across a span of about 800 m east to west is enclosed in stone. Wakisaka Yasuharu, who took over in 1585, rebuilt the castle in stone to guard Toyotomi Hideyoshi's Osaka Castle from the sea. Most walls are rough natural stone (nozura-zumi), but some corners use shaped stones laid in alternating directions (sangi-zumi).[1][3]
Can you see it?
Visible from outsideOpen free at all times as a park.
At a glance for visitors
Nearest station
35 min walk from Sumoto Bus Center (highway buses)
Climb
Steep climb
Time neededEditors' estimate
About an hour for the upper castle; half a day if you add the lower castle and the museum.
Admission
Adults 500 yen; high school and university students 300 yen; elementary and junior high students 150 yen (group discounts available).
Hours
9:00–17:00 (last entry 16:30)
Access
Open to visitors
The upper castle is a park and historic site, open free at all times. Lighting is limited, so bring a flashlight after dark. The mock keep cannot be entered. The Continued Top 100 stamp and goshuin-style castle seals are at the Awaji Culture Museum in the lower castle (closed Mondays).
Sumoto Castle stands on Mt. Mikuma, about 130 m high, south of the town of Sumoto. Tradition says it was built in 1526 by the Ataka clan, leaders of the Awaji navy in the Sengoku period (another account gives 1510). It was a sea-facing fortress overlooking the Kitan Strait and Osaka Bay.[1][3]
02
Historical record
Wakisaka Yasuharu rebuilds it in stone
In 1582 Hideyoshi's retainer Sengoku Hidehisa became lord, and from 1585 Wakisaka Yasuharu, one of the "Seven Spears of Shizugatake," held the castle for 24 years. He rebuilt it entirely in stone as a stronghold protecting Hideyoshi's Osaka Castle. Roof tiles bearing the Wakisaka crest, and tiles in a Korean style, have been excavated from the main and east enclosures.[1][3][8]
03
Scholarly interpretation
Climbing walls and the Korean campaigns
Yasuharu led the Awaji navy in Hideyoshi's invasions of Korea in 1592 and 1597. The climbing walls running down the mountainside are thought to be related to the wajo castles the Japanese built in Korea at that time, and are estimated to date from the 1590s to early 1600s.[3][2]
04
Historical record
Abandoned, then revived by the "Yura move"
When the Wakisaka moved to Ozu in Iyo in 1609, the mountaintop castle was in effect abandoned. After the Siege of Osaka, Awaji passed to the Hachisuka family of the Tokushima domain, whose senior retainers the Inada were based at Yura. Yura proved inconvenient, so in 1631–1635 the castle and the whole town were moved to Sumoto, an event called the "Yura-biki" (Yura move). The lower castle built at the foot of the mountain then served as the seat of government for Awaji until the Meiji era.[1][3][2]
05
Historical record
No buildings, but the walls remain
None of the castle buildings survive. The lower castle's palace was torn down in the early Meiji era; one part, the Kintenkaku, was moved to Sumoto Hachiman Shrine and still stands there. On the summit, the main, south and east enclosures, the Mushadamari bailey and others remain with their stone walls and a large pond.[1][3]
06
Historical record
The mock keep and site conservation
After the Meiji era the summit ruins were opened as a park. In 1928, work began on a reinforced-concrete mock keep on the keep base to mark Emperor Showa's enthronement, and it was finished in 1929. The upper castle became a National Historic Site in 1999 and the lower castle a city historic site, and in 2017 Sumoto was chosen as No. 164 of the Continued Top 100 Japanese Castles. The city continues conservation work, mainly repairing the stone walls.[1][3][4]
The upper castle is designated a National Historic Site[1]
Selected as No. 164 of the Continued Top 100 Japanese Castles[1][4]
Buildings and remains
The keep today
Mock keep
A reinforced-concrete mock keep (a castle-shaped rest house), begun in 1928 and completed in 1929. It does not reproduce a historical keep. Closed to visitors because of its age.
The site today
The upper castle on the summit is open free at all times as Mikumayama Park, with stone-walled baileys and the mock keep, plus a café inside the main enclosure. The lower castle at the foot keeps its walls and moat, with the Awaji Culture Museum and courthouses on the site.
Main buildings
Modern reconstruction
Mock keep
Built to mark Emperor Showa's enthronement. Exterior only.[1][3]
Original, relocatedHyogo Prefectural Cultural Property
Kintenkaku (part of the lower castle's palace)
Moved after the Meiji Restoration; now in the grounds of Sumoto Hachiman Shrine.[3][6]
Stone walls, Keep base (tenshudai), Moats, Baileys / enclosures (kuruwa), Fortified gateways (koguchi)Editorial article
Designation
National Historic Site (Sumoto Castle ruins, upper castle) (1999); Sumoto City Historic Site (lower castle)Editorial article
Selection
Next 100 Fine Castles No. 164Japan Castle Foundation
Visiting
Access
Open to visitors
The upper castle is a park and historic site, open free at all times. Lighting is limited, so bring a flashlight after dark. The mock keep cannot be entered. The Continued Top 100 stamp and goshuin-style castle seals are at the Awaji Culture Museum in the lower castle (closed Mondays).
Sumoto Bus Center (highway buses)Highway buses from Osaka, Sannomiya, Shin-Kobe, Kosoku Maiko, Tokushima and elsewhere
about 35 min walk · Steep climb
About 35 minutes on foot up Mt. Mikuma to the upper castle. The lower castle (Awaji Culture Museum) is about 10 minutes from the bus center.[5][7]
Checked: 2026-10-03
Hours and admission
Sumoto City Awaji Culture Museum (lower castle)
Hours
9:00–17:00 (last entry 16:30)
Closed
Mondays (or the next weekday if Monday is a holiday)
Admission
Adults 500 yen; high school and university students 300 yen; elementary and junior high students 150 yen (group discounts available).[7]
Checked: 2026-10-03
By car / parking
About 15 minutes from Sumoto IC or Awajishima Chuo Smart IC on the Kobe-Awaji-Naruto Expressway. All upper-castle lots are free and always open: Umaya-ato lot (about 10 cars, 6 min to the keep base, narrow road, no buses, no toilet); Sumoto Castle Ruins lot (about 20 cars, 8 min, 1 bus space, toilet); Mikuma Ikoigaoka lot (about 50 cars, 14 min, 2 accessible spaces, toilet); Mikumayama East lot (about 35 cars, 16 min, toilet).[1][5]
About an hour for the upper castle; half a day if you add the lower castle and the museum.
Steps, slopes and footing
The upper castle is on a mountaintop; even from the parking lots you walk up steps and slopes. Climbing from town is a mountain walk of about 35 minutes.[1][5]
Wheelchairs and strollers
The Mikuma Ikoigaoka lot has two accessible parking spaces. Step-free routes within the ruins are not confirmed.[1]Checked: 2026-10-03
Toilets and rest
Toilets at three of the parking lots. The toilet at the rest house in front of the main stairway was out of order as of September 25, 2026.[1]
English signs / audio guide
Not confirmed
Seasons
Cherry blossoms in spring. The Sumoto Castle Festival is held every November 3.[5]
Photography
No city permit is needed to fly drones, but follow aviation law and be considerate of others.[1]
Works, closures and restrictions
The rest-house toilet in front of the main stairway was out of order as of September 25, 2026. The 046cafe in the main enclosure is open 9:00–16:00, closed Tuesdays and Wednesdays. Volunteer guides (Sumoto Castle Friends) must be booked by phone at least a week ahead (0799-25-5820).[1]Checked: 2026-10-03
City museum on the site of the lower castle, covering Sumoto Castle's history and excavated finds. The Continued Top 100 stamp is kept here.[7][1]
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
Good for stone-wall fans, anyone who loves a view over sea and town, and travelers driving around Awaji Island. By car, the main enclosure is only minutes from the parking lots.
What makes it interesting
The stone-walled baileys spread across the summit, the Great Stone Stairway, and the view of Osaka Bay from the keep base. The mock keep is best enjoyed as a piece of Showa-era commemorative architecture. If time allows, look for the climbing walls on the slope and the walls and moat of the lower castle to understand how the two castles fit together.
Before you go
No original buildings survive, and the keep is a Showa-era mock keep you cannot enter. The upper castle is on a mountain, about 35 minutes' climb on foot. The stamp is at the museum in the lower castle, which closes on Mondays.
Ways to enjoy it
Take a break at the café in the main enclosure while looking out to sea, or time your visit for the Sumoto Castle Festival on November 3. You can also stay at Sumoto Onsen at the foot of the mountain and climb to the castle in the morning.
Photos
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Open questions
Two founding dates are given: 1526 (Ataka Haruoki) and 1510 (another member of the Ataka family).
Sources give either 1928 or 1929 for the mock keep; the city's conservation plan says construction began in 1928 and was completed in 1929.
The "oldest mock keep in Japan" claim comes from Sumoto City and the Hyogo tourism website.
The link between the climbing walls and the castles in Korea is an estimate. Where to view the climbing walls and English signage could not be confirmed.
