The Smallest of the Twelve Original Keeps
Marugamejo Tenshu (丸亀城天守, also written Marugame-jō Tenshu), the main keep of Marugame Castle at Ichiban-cho in Marugame City, Kagawa Prefecture, is a three-storey wooden tower completed in 1660 and designated an Important Cultural Property on 9 June 1943.
It is the smallest surviving original keep in Japan. Twelve castle towers escaped the demolitions of the Meiji era, the fires of the war, and the earthquakes in between, and of those twelve this one stands lowest, at roughly fifteen metres. It also sits on the tallest stonework of any of them, which is the whole point of the place.
The keep rises from the summit of Kameyama, a hill of about sixty-six metres that gives the castle its alternative name, Kameyama Castle. Marugame is a hirayama-jiro, a castle built on high ground within a plain. The site holds the honmaru, ninomaru and sannomaru enclosures along with the obikuruwa and yamashita-kuruwa, and the designated historic site inside the inner moat covers 204,756 square metres across a plot roughly 540 metres east to west and 460 metres north to south.
The Agency for Cultural Affairs records the structure as a three-tier, three-storey turret roofed with formal round-and-flat tiling, and lists a wooden plaque among the attached items covered by the designation. It gives the construction period as 1643 to 1660, which spans two ruling houses.
Why It Was Built Small
Ikoma Chikamasa raised the first castle on Kameyama in 1597. It did not last. The shogunate's one-castle-per-province edict of 1615 closed it down, and Marugame stood abandoned for nearly thirty years. When western Sanuki was split off as a separate domain, Yamazaki Ieharu received permission to rebuild and began work in 1643. Kyogoku Takakazu took over the domain in 1658 and saw the keep finished in 1660. The full reconstruction of the walls continued until 1673.
Through the Edo period the building was never called a tenshu. It was the gosankai-yagura, the three-storey turret. A domain of sixty thousand koku did not advertise a keep to the shogunate, and the modest scale and the modest name worked together. The restraint is legible in the elevation: a small chidori gable and a small karahafu gable on the front face, and very little else.
The designation date of June 1943 belongs to the pre-war National Treasures Preservation Law. When the Law for the Protection of Cultural Properties came into force in 1950, buildings on that earlier list became Important Cultural Properties, and the original date stayed on the record. The keep was dismantled and rebuilt for repairs in 1950, and the first Marugame Castle Festival was held to mark the completion of that work.
The two gates at the main entrance carry their own designations. Ote Ichi-no-mon, a turret gate also known as the Drum Gate for the time-drum the domain retainers beat inside it, and Ote Ni-no-mon, a korai-style gate, were both rebuilt in 1670 and listed in 1957. The masugata courtyard between them measures about eighteen metres north to south by twenty metres east to west, considerably larger than the standard the military manuals of the period prescribed.
Reading the Stonework on the Way Up
The climb from the main gate to the keep passes through several centuries of masonry technique, and Marugame City's own guide to the walls identifies ten specific things to find.
- Kagami-ishi, display stones over two metres across, set into the masugata at the main gate
- Uchikomi-hagi, the split-and-dressed technique that forms most of the castle's principal walls, with horizontal joints running level
- Sangi-zumi corner work on the sannomaru, where the north face toward the Seto Inland Sea exceeds twenty metres in height
- Nozura-zumi, undressed natural stone, on the southeastern lower slope
- Habaki-ishigaki on the west side of the honmaru, an outer sheath built in the Yamazaki period to hold a bulging wall in place without dismantling what stood on top of it
- Fire-reddened granite near the sannomaru, scorched when the domain residence burned in 1869
The four tiers of walling stacked from the foot of the hill to the summit are commonly given a combined height of around sixty metres and described as the tallest in Japan. Stand at the moat and look up and the claim needs no arithmetic.
Heavy rain in 2018 brought down the west face of the obikuruwa wall and the wall at the site of the sannomaru southwest turret. Restoration has been under way since. Marugame City publishes progress updates, and a dedicated exhibition building near the collapse site explains the work, displays stonemasons' tools and excavated material, and has a rooftop deck overlooking the site.
Inside the keep, the stairs are steep and the ceilings low, in the manner of every surviving tower of this age. The top floor looks out over the city to the Seto Inland Sea, the Seto Ohashi bridge, and Iino-yama, the cone that locals call Sanuki Fuji. The turret sites on the honmaru have been laid out as viewing platforms.
The keep is open from 9:00 to 16:30 with last entry at 16:00, and there are no regular closing days. Admission is 400 yen for adults and free for junior high school students and younger. Cash, credit cards, transport IC cards and QR payments are all accepted. The interior of Ote Ichi-no-mon is open free of charge on the same hours. A combined ticket with the Nakazu Bansho-en garden costs 900 yen. The walk from JR Marugame Station takes about ten minutes.
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Q&A
- What are the opening hours and admission fee for Marugame Castle Tenshu?
- The keep opens 9:00 to 16:30 with final admission at 16:00, and has no regular closing days. Adults pay 400 yen and junior high school students and younger enter free. Groups of twenty or more receive a twenty percent discount, and Marugame residents aged sixty-five and over enter free on production of identification.
- Is Marugame Castle Tenshu an original structure or a reconstruction?
- It is original. Completed in 1660, it is one of the twelve castle keeps in Japan that survive from before the Meiji era, and the smallest among them at about fifteen metres. It underwent a full dismantling repair in 1950 but the fabric is historic.
- Are the collapsed stone walls at Marugame Castle still under repair?
- Yes. Sections of the obikuruwa west face and the sannomaru southwest turret site came down after heavy rain in 2018 and restoration continues. The keep itself remains open. Marugame City posts progress updates, and an exhibition building near the site explains the project.
- How do I get to Marugame Castle Tenshu from the station?
- JR Marugame Station is about ten minutes on foot from the castle's main gate. The climb from the gate up to the keep takes a further fifteen to twenty minutes on stone-paved slopes, so proper footwear helps.
- Why was Marugame Castle Tenshu called a gosankai-yagura during the Edo period?
- Calling it a three-storey turret rather than a keep was a gesture of deference toward the Tokugawa shogunate. A domain assessed at sixty thousand koku had reason to keep both the building and its name understated.
Basic Information
| Name | Marugamejo Tenshu (丸亀城天守) |
|---|---|
| Location | Ichiban-cho, Marugame City, Kagawa Prefecture |
| Designation | Important Cultural Property (Building), designation number 01060 |
| Year Designated | 9 June 1943 |
| Quantity | 1 building; attached item: 1 wooden plaque |
| Dimensions | Three-tier, three-storey turret with formal round-and-flat tiling; approximately 15 metres tall |
| Owner | Marugame City |
| Public Access | Open 9:00 to 16:30 (last entry 16:00), no regular closing days. Adults 400 yen, junior high school students and younger free |
References
- National Cultural Properties Database (Agency for Cultural Affairs) — Marugamejo Tenshu
- https://kunishitei.bunka.go.jp/heritage/detail/102/3286
- Cultural Heritage Online — Marugamejo Tenshu
- https://bunka.nii.ac.jp/heritages/detail/191123
- Marugame City — Viewing Hours and Admission
- https://www.city.marugame.lg.jp/site/castle/7454.html
- Marugame City — About Marugame Castle
- https://www.city.marugame.lg.jp/site/castle/2907.html
- Marugame City — Guide to the Stone Walls
- https://www.city.marugame.lg.jp/site/castle/2920.html
- Marugame City — Stone Wall Restoration Updates
- https://www.city.marugame.lg.jp/site/castle/list13.html
Last verified: 2026.08.09