Kochi Castle Honmaru Palace: One of Only Two Surviving Edo-era Palace Buildings in Japan

Last updated： July 12, 2025

Step Into a Rare Original Edo-period Palace at Kochi Castle

Inside Kochi Castle grounds, with the keep and surrounding stone walls creating a picturesque view.

Kochi Castle was constructed in the early Edo period as the base of the Tosa Domain. The standout feature is the Honmaru Palace, a structure of tremendous historical and architectural value—one of only two surviving Honmaru Palaces in all of Japan.

It is also the only castle in Japan where both the original keep and palace remain intact, providing a rare chance to immerse yourself in the world of Edo-period feudal politics and samurai culture.

This article introduces the Kochi Castle Honmaru Palace, also known as Kaitokukan.

Kochi Castle Honmaru Palace (Kaitokukan)

Entrance to Kaitokukan. The aged texture of the wood reflects the passage of time.

Located in Kochi City, Kochi Prefecture, the Honmaru Palace is a surviving Edo-period (17th–19th century) castle structure. Once used by the feudal lord for official ceremonies and receptions, it is now open to the public as a valuable historical site.

Business hours: 9:00 am - 5:00 pm (Last admission at 4:30 pm)
Regular holiday: December 26 to January 1
Fee: ¥500 (Free for those under 18, student ID required)
Telephone number: +081-88-824-5701
Official site: https://kochipark.jp/kochijyo/
Parking: On - site parking available (7:30 am–6:30 pm / ¥370 for the first hour, then ¥110 per 30 minutes)
How to visit: Approx. 25 minutes on foot from JR Kochi Station, 5 minutes on foot from Kochijomae tram stop (Tosaden Transportation)
Address: 1 - 2-1 Marunouchi, Kochi City, Kochi Prefecture 780 - 0850

Only Two in Japan: A Rare Surviving Honmaru Palace

There are only two surviving Honmaru Palaces in all of Japan today.

One is the Kawagoe Castle Honmaru Palace in Saitama Prefecture. The other is this one at Kochi Castle.

Most castles lost their palaces during the Meiji Restoration or due to war. The preservation of Kochi Castle’s Honmaru Palace makes it an incredibly rare example.

Even more uniquely, Kochi Castle is the only castle in Japan where both the original keep and Honmaru Palace remain intact.

Exterior view of the keep and Honmaru Palace, both designated cultural assets.

It is the only place in the country where you can experience the original spatial layout from the palace to the keep.

History of Kochi Castle and the Honmaru Palace

Historical image of the keep and 'Kaitokukan' calligraphy displayed at the entrance.

Construction of Kochi Castle began in 1601.

The first lord of the Tosa Domain, Yamauchi Katsutoyo, was granted control of the region as a reward for his service in the Battle of Sekigahara. He built the castle as his political base.

The castle took 10 years to complete and was finished in 1611. The Honmaru Palace was completed in 1603.

It served as the domain lord’s ceremonial and administrative hub. Before the Ninomaru Palace was completed, it was also said to have been the lord’s residence.

Although the original was destroyed in a fire in 1727 along with the keep, it was rebuilt by 1747 and remains faithful to its Edo-period construction to this day.

The Honmaru Palace features a one-story, irimoya-style structure with hon-gawara tiled roofing—a textbook example of feudal palace architecture.

Full view of the Honmaru Palace exterior, showcasing the traditional wooden structure and tiled roof.

One Story: Refers to a single-floor structure. In Japanese architecture, 'story' indicates the number of floors—'one story' means a ground-level building. The Honmaru Palace is built on a single level.

Irimoya-style Roof: A traditional Japanese roof design combining gabled and hipped elements. The upper part is gabled while the lower is hipped, creating a graceful and complex silhouette. This style is often seen in temples, shrines, castles, and samurai residences for its prestige and structural stability.

Hon-gawara Roofing: A prestigious tiling technique using rounded and flat tiles alternately. It is durable, heavy, and used for important buildings like castles and temples. Unlike thatched roofs seen in commoners' homes, this style indicates social rank and authority.

The name Kaitokukan was adopted in the Meiji era (from the 1870s) when the castle was transferred to Kochi Prefecture. It is now the official designation of the Honmaru Palace.

Shoin-zukuri: Architectural Elegance of the Samurai Era

Kaitokukan was built in the Shoin-zukuri style, a refined architectural approach that epitomizes samurai-era aesthetics.

Shoin-zukuri: An architectural style that emerged in the 15th century and was refined in the early 17th century. Evolving from the aristocratic 'shinden-zukuri' style of the Heian period, Shoin-zukuri adapted to samurai lifestyles and emphasized functionality, formality, and symmetry.

Inside, rooms with tatami mats are softly partitioned by shoji and fusuma, creating a calm and orderly ambiance. Elegant transoms with wave motifs and raised platforms add ceremonial grandeur to the space.

Interior view of Kaitokukan. Tatami rooms flow seamlessly together.

The structure includes sliding doors and railings designed to let in natural light.

Verandas and hallways at the building’s edge connect the rooms to the garden, harmonizing architecture and nature. Carefully positioned openings frame views of the garden, incorporating natural beauty into the orderly space.

Hallway with a sense of openness, emphasizing unity between the palace and garden.

View from the veranda. The outer wall features loopholes for observing and defending.

A small garden offers a peaceful resting area.

Rather than relying on opulence, Kaitokukan expresses elegance through materials, proportions, and light—realizing the Shoin ideal of refined simplicity.

The Jodan-no-ma (Lord’s Chamber)

At the center of the Honmaru Palace lies the Jodan-no-ma, its most prestigious room.

View of the Jodan-no-ma from the south corridor. The elevated floor can be clearly seen.

This space was used by the lord for ceremonies and receiving guests. Its floor is raised and features elements such as oshita and chigaidana shelves, symbolizing authority.

Interior of the Jodan-no-ma, showing chigaidana and other Shoin-style elements.

A notable feature is the Musha-kakushi (hidden warrior space), a concealed room for guards to hide in preparation for emergencies.

Chodai-kamae structure with modest design but gold leaf on family crests.

Behind the decorative doors is a storage space known as a nando. Though it looks like a simple closet, it was cleverly designed for guards to spring into action when needed.

Behind the Scenes of the Musha-kakushi

Behind the Musha-kakushi doors lies a nando, a small concealed room now open to visitors.

Though it appears to be for storage, it was used by bodyguards who would lie in wait to protect the lord if danger arose.

Interior of the nando room, where warriors would hide in case of emergency.

This subtle but strategic design reflects the castle’s deep concern for security even in ceremonial spaces.

Visitor Route Through Kaitokukan and the Keep

Exterior view showing Kaitokukan and the keep side by side.

Kaitokukan is connected directly to the castle keep. The standard visitor route flows from the Honmaru Palace to the keep. Admission covers both areas for ¥500.

Map showing the visitor route from Kaitokukan to the keep.

Enter through the Kaitokukan entrance and pay the admission fee.
Follow the path through the fourth and third rooms, arriving at the south corridor.
From the corridor, view the Jodan-no-ma and the courtyard garden.
Before entering the keep, take a short detour to see the Musha-kakushi area (nando).
Proceed into the keep.
After visiting the keep, return through Kaitokukan and exit.

Experience the Authentic Atmosphere of Edo-Era Architecture

Entrance hall of Kaitokukan, featuring an old photo of the castle and a calligraphy piece.

As one of the few surviving Honmaru Palaces in Japan, Kaitokukan holds immense architectural and historical value.

From the Jodan-no-ma, where ceremonies took place, to the Musha-kakushi, and the nature-integrated verandas—every space preserves the formal atmosphere of the Edo period.

Though castle keeps often draw the most attention, Kochi Castle offers a deeper historical experience through Kaitokukan.

Unlike reconstructed buildings found elsewhere, this is the original, allowing visitors to engage with authentic Japanese history.

If you visit Kochi Castle, be sure to explore Kaitokukan—one of only two original Honmaru Palaces remaining in Japan.