Confidence
| Field | Confidence | Notes |
|---|---|---|
| Castle name | 99% | Center stylized brushwork unambiguously reads 高松城 (Takamatsu-jō); the right-column brush 「日本三大海城」 ("Japan's Three Great Sea Castles") is a distinguishing identifier shared by Takamatsu, Imabari, and Nakatsu — and combined with the OshiroBots robot silhouette this exact design is documented as the official Takamatsu Castle OshiroBots gojōin. Top-right red square 御城印 seal confirms the gojōin classification. |
| Date | N/A | Date column 令和 年 月 日 left blank — typical of pre-printed gojōin sold at castle shops. Late March 2025 based on this book's Shikoku trip placement (Takamatsu sits naturally in a Matsuyama → Takamatsu → Okayama itinerary). |
Identification
- Name (Japanese): 高松城 (オシロボッツ版)
- Name (Romanized): Takamatsu-jō (OshiroBots edition)
- Type: 御城印 (gojōin / castle stamp) — collaboration design with 城郭合体オシロボッツ (Oshiro Robots / "Castle Fusion OshiroBots"), a MIXI ANIME original IP that turns famous Japanese castles into transforming-mecha characters
- Issuance point: Tamamo Park (玉藻公園) ticket office — Takamatsu Castle ruins
- Location: Tamamo-chō, Takamatsu, Kagawa Prefecture, Shikoku
- Date received: Date column blank; late March 2025 (estimated from trip context)
Reading the gojōin
| Element | Reading | Position |
|---|---|---|
| 御城印 (tensho seal) | "Castle stamp" certification mark | Top center, red square seal |
| 日本三大海城 | "Japan's Three Great Sea Castles" | Right column, brush |
| 高松城 | Takamatsu-jō (Takamatsu Castle) | Center, large stylized brush over the OshiroBot |
| 高松城 OshiroBot illustration | Anime mecha rendering of the castle as a robot — body is the keep, arms are turrets, the Hiryū-maru (飛龍丸) ceremonial ship is on the back; the red disc behind suggests the Matsudaira sun/moon motif | Center, line-drawing + red disc |
| Takamatsu Castle line drawing (background) | The actual castle keep silhouette and surrounding turrets/walls | Background, faint line drawing |
| 城郭合体オシロボッツ ©MIXI | Series logo and copyright | Bottom center |
| 令和 年 月 日 | Date column (Reiwa year/month/day) — left blank | Left side |
What's a gojōin? And what's OshiroBots?
御城印 (gojōin / castle stamp)
A gojōin is a commemorative stamp issued by a Japanese castle (or the museum/park that manages its ruins). It's the secular castle-equivalent of a goshuin (the religious stamp issued by Buddhist temples and Shinto shrines), and most goshuincho (stamp books) holders mix the two freely. Gojōin became popular in the 2010s, modeled deliberately on the goshuin tradition. Each costs roughly 300 yen. They're sold at the entrance/ticket office or castle gift shop, not by religious staff, and have no religious meaning — they're souvenir-collectible stamps proving you visited.
城郭合体オシロボッツ (OshiroBots)
「城郭合体オシロボッツ」 is an original-content franchise launched in December 2022 by MIXI ANIME that re-imagines real Japanese castles as transforming giant robots (mecha). The naming pattern jōkaku-gattai (城郭合体, "castle fusion") riffs on classic anime tropes from Mazinger Z, Voltron, and Getter Robo. The first three castles announced were:
- Kumamoto Castle (熊本城)
- Takamatsu Castle (高松城) — this stamp
- Aizu-Wakamatsu Castle (会津若松城)
By 2024 the lineup had expanded to over 10 castles including Fukuyama, Nagoya, Hikone, Matsumoto, Himeji, Okayama, and others. Collaborative gojōin priced 300 yen each were first sold at the Shiro EXPO 2023 (December 2023) and have since become available at each respective castle's gift shop.
The Takamatsu OshiroBot in this stamp is composed of:
- Body: the central castle keep (天守 / tenshu)
- Right arm: the moon-viewing turret (月見櫓 / Tsukimi-yagura) — one of the rare Edo-period structures still standing here
- Left arm: the northeast corner turret (艮櫓 / Ushitora-yagura)
- Feet: the corridor/connecting tower (渡櫓)
- Backpack: the Matsudaira clan's ceremonial ship 飛龍丸 (Hiryū-maru / "Flying Dragon Boat")
About Takamatsu Castle
Takamatsu Castle was built starting 1588 by 生駒親正 (Ikoma Chikamasa), the daimyo who received Sanuki Province (modern Kagawa) under Toyotomi Hideyoshi. The castle is a flatland-on-water (海城 / umi-jiro — "sea castle") type, with its inner moats fed directly by tidal seawater from Seto Inland Sea — fish caught in the inner moat are still saltwater species (sea bream, mullet) rather than freshwater carp.
In 1642 the castle was transferred to 松平頼重 (Matsudaira Yorishige), a son of Tokugawa Yorifusa and grandson of Tokugawa Ieyasu — making this the seat of a Mito Tokugawa cadet branch (Takamatsu-Matsudaira) for the rest of the Edo period. The castle keep was demolished in 1884 during early-Meiji modernization. Surviving structures from the Edo period include:
- 月見櫓 (Tsukimi-yagura) — moon-viewing turret, ICP since 1950
- 艮櫓 (Ushitora-yagura) — northeast corner turret, ICP since 1950
- 渡櫓 (Watari-yagura) and 披雲閣 (Hi'unkaku) garden pavilion — both surviving Edo/Meiji structures
The grounds are now 玉藻公園 (Tamamo Park) — "Tamamo" referring to a Man'yōshū poem that praises the seaweed-filled coast of this area, which gave Takamatsu its old poetic name Tamamo-no-Ura.
"Japan's Three Great Sea Castles" (日本三大海城)
The right-column brush proudly declares Takamatsu one of the 三大海城 / san-dai umi-jiro — Japan's Three Great Sea Castles, all of which take seawater directly into their moats:
- 高松城 (Takamatsu) — Kagawa, Shikoku
- 今治城 (Imabari) — Ehime, Shikoku
- 中津城 (Nakatsu) — Ōita, Kyushu
(Some lists substitute Sakai/三原 (Mihara) for Nakatsu — the grouping is informal.)
What it's known for
- The only castle in Japan with sea-fish swimming in its moats — a unique selling point for visitors
- The moon-viewing turret (月見櫓) is one of the most photographed Edo-period structures in Shikoku, particularly at sunset
- A free boat tour (城舟体験) lets visitors row a small wasen through the inner moat
- Cherry-blossom and plum-blossom seasons are major draws