Former Ako Castle Gardens / Honmaru Gardens / Ninomaru

An Edo-Period Garden Recovered from the Ground

Most Japanese gardens that survive from the seventeenth century have been tended without a break for generations. The gardens of Akō Castle took a different path. Once the castle lost its purpose in the Meiji era, the grounds passed into private hands and were turned over to rice fields and vegetable plots. The ponds were filled in. For more than a century, the only proof that gardens had ever stood here lay buried beneath the soil.

What visitors walk through today in the city of Akō, in southwestern Hyōgo Prefecture, is the result of decades of excavation. Archaeologists uncovered pond beds, stone-paved channels, and shoreline construction in enough detail that the two gardens could be rebuilt close to their original form. Together they carry the name Former Akō Castle Garden, covering the Honmaru Garden and the Ninomaru Garden, and in September 2002 they were designated a national Place of Scenic Beauty.

A Castle Built on the Edge of the Sea

Akō Castle began in 1645, the year Asano Naganao moved his household here from Kasama in Hitachi Province. Construction ran from 1648 to 1661, an unusually long span for a castle of this size. The design was entrusted to Kondō Masazumi, a retainer trained in the Kōshū school of military science. His teacher, the Confucian scholar Yamaga Sokō, spent several months in Akō while the work was underway and is credited with shaping parts of the layout.

This was a flatland fortress, and its southern walls once met the Seto Inland Sea directly. Boats could approach the ramparts. Fresh water came from the upper reaches of the Chikusa River, carried by an engineered supply system that reached individual houses in the castle town. The same network fed the ponds inside the castle. That is why two large water gardens could be sustained on a coastal site with no natural stream running through it.

Akō is bound up with one of the most retold episodes in Japanese history. In 1701 the third Asano lord, Naganori, drew his sword against a court official inside Edo Castle and was ordered to die the same day. His domain was dissolved. The following winter, forty-seven of his former retainers, led by Ōishi Kuranosuke, carried out a revenge that became the basis for the Chūshingura story. After the Asano line ended, the Mori family held Akō until the Meiji Restoration, and it was under the Mori that parts of the Honmaru Garden were altered in the later Edo period.

Why the Gardens Were Designated

Many daimyo gardens survive in Japan, but they usually come as isolated examples: one garden attached to one residence. Akō is unusual because a single castle held two large pond gardens, one in the Honmaru and one in the Ninomaru, and both have been recovered and preserved as a connected whole. The Agency for Cultural Affairs cited exactly this when it designated the site, describing it as the first daimyo garden conserved with its honmaru and ninomaru sections treated as one unit.

The excavation also produced something a continuously maintained garden could never offer: physical evidence of how the gardens changed over time. In the Honmaru large pond, archaeologists identified roughly three phases of reconstruction, with successive pond beds and stone arrangements layered one over another. The restored garden was laid out so that this sequence stays legible to anyone who looks closely. For specialists the site matters less as a beautiful object than as a record of how a domain actually used its gardens across the Edo period.

The Honmaru Garden: Three Ponds Around the Palace

The Honmaru Garden surrounded the lord's palace and is built around three separate bodies of water. The largest sits on the south side of the main hall. Its shoreline is shaped into miniature capes and inlets, with a central island and scenic stones set in considered positions. Look down into the water and the pond bed itself becomes the attraction: flat stones and roof tiles arranged in geometric patterns, with stretches of gravel between them. This decorated bed is uncommon, and showing it clearly is one reason the garden was restored with the water kept shallow.

In an inner courtyard behind the palace lies a pair of small ponds set side by side. Water enters the western pond, which has a bed of rounded stones, then slips into a boat-shaped basin on the eastern side before draining toward the great pond through a covered culvert. The banks here were finished with plaster studded with pebbles, a painstaking technique that gives them a pitted, hail-scattered texture.

The third pond, in the northwest corner, was a complete surprise. It appears on no surviving map of the castle. Archaeologists found it only by digging, and among the finds were wooden tablets inscribed with personal names, including those of Asano Naganori and Ōishi Kuranosuke. The pond has two parts: a rectangular southern basin lined with flat stone slabs, and an oval northern basin left rougher, with paving only along the waterline.

Above the garden rises the stone base of the keep, about nine meters tall. No tower was ever built on it. Climbing the base gives the clearest view of how the three ponds relate to one another and to the footprint of the vanished palace.

The Ninomaru Garden: A Garden Made for Boats

The Ninomaru Garden is the larger of the two and was laid out on a different principle. It stretches from the south side of a senior retainer's residence across to the western partition of the second enclosure, covering roughly eighteen thousand square meters. The residence belonged to Ōishi Yoshishige, known as Tanomosuke, a domain elder and a great-uncle of Ōishi Kuranosuke. Visitors now enter the garden through the gate of that residence.

The garden has two distinct moods. The section near the residence reads as a stream: a shallow, carefully worked channel with a bed of rounded stones and flat slabs, fed by a water inlet at the tip of a small cove so that the current moves with an easy, unhurried flow. This part was made to be studied at close range.

The southwestern section is something else entirely. Here the water deepens into a broad pond called Kintai-ike, large enough for a boat. Two islands sit within it, and the remains of a bridge have been confirmed. A slight difference in water level separates the quiet stream from this open expanse. Yamaga Sokō, the scholar who had been exiled to Akō, left a note describing an outing by boat on Kintai-ike, which is how the pond's name and its use for pleasure boating came to be known.

Planning a Visit

Both gardens lie within the grounds of the Akō Castle ruins and can be seen on a single walk. The Honmaru and Ninomaru gardens open from 9:00 to 16:30, with last entry at 16:00, and admission is free. They close over the New Year period, from December 28 to January 4; the rest of the castle grounds stay open year round. Restoration is still in progress in places, so a section may occasionally be fenced for ongoing work.

From Banshū-Akō Station on the JR Akō Line, the castle is about a fifteen to twenty minute walk. Drivers coming from the Sanyō Expressway can reach the site in roughly ten minutes from the Akō interchange, and free parking is available. Allow at least an hour to take in both gardens at an unhurried pace. The contrast between the Honmaru ponds and the open water of the Ninomaru is easier to appreciate without rushing.

Beyond the Gardens

The castle grounds hold more than the two gardens. The Honmaru gate and several other structures have been rebuilt through the same combination of excavation, old drawings, and historic photographs. Two genuine Edo-period buildings still stand in the third enclosure: the long gatehouse of the Ōishi residence and the gatehouse of the Kondō Genpachi house.

A short walk away is Ōishi Shrine, founded in 1900 on the site of the Ōishi family residence and dedicated to the forty-seven retainers. Its treasure hall displays weapons and documents connected to the revenge of 1702. The Akō City Museum of History, near the castle, gives useful background on the domain, its noted salt production, and the water-supply system that made the castle gardens possible. For another garden in the area, the privately held Tabuchi Family Garden lies a few kilometers off, though it opens to the public only on rare occasions.