A Strategic Location Overlooking the Kumano River
A Hill Between the River and the Sea
Tanzaku Hill stands on the southern bank of the Kumano River, close to where the river flows into the sea. From the summit, visitors can look across the river toward Shingu’s urban area and out toward the Pacific Ocean. This commanding view explains why the castle was also known as Okimi Castle, a name associated with looking out toward the open sea.
The location had been important long before the construction of the castle. According to tradition, a residence belonging to the Kumano Betto, a high-ranking religious and administrative leader associated with the Kumano region, once stood here during the late Heian period.
Another local tradition tells of Princess Tanzaku, said to have been a daughter of Minamoto no Tameyoshi. Her connection with the hill is believed to have inspired the name Tanzaku Castle.
A Center for Transportation and Trade
The castle’s strategic value was not limited to military defense. Its position beside the Kumano River allowed it to take advantage of the river’s transportation network. Boats could carry people and goods along the waterway, making the area an important center for logistics, commerce, and regional economic activity.
For this reason, Shingu Castle played an important role not only as a fortress but also as part of the economic infrastructure of the Kumano region.
From the Warring States Era to the Edo Period
Construction Under the Asano Family
The foundations of the present-day castle were established around 1601, during the early Edo period, by Asano Tadayoshi, a senior retainer of Asano Yoshinaga, a powerful lord who served under Toyotomi Hideyoshi. Construction was largely completed by the following year.
The project transformed Tanzaku Hill into a substantial early-modern Japanese castle. A temple that had stood on the hill was relocated, while large stone walls were constructed to strengthen the defensive system.
However, the castle’s history soon took a major turn. In 1615, the Tokugawa shogunate introduced the One Castle per Province policy, known as ikkoku ichijōrei. As a result, Shingu Castle was temporarily abandoned.
The Mizuno Family Completes the Castle
The castle was revived in 1619, when Tokugawa Yorinobu became lord of the Kishu Domain. Mizuno Shigenaka, one of Yorinobu’s senior hereditary retainers, became the lord of Shingu and took over the development of the castle.
The Mizuno family expanded and improved the existing fortress. By 1633, a castle complex centered around a main keep had been completed, and additional stone walls and moats were constructed over the following years.
Much of the impressive stonework visible today dates from the period of Mizuno rule. The Mizuno family governed Shingu for approximately ten generations, contributing to the development of the surrounding castle town.
Even today, elements of Shingu’s historic urban landscape reflect the area’s long connection with the castle and its former lords.
Impressive Stone Walls and Castle Layout
The original buildings, including the castle keep and watchtowers, no longer survive. However, the site retains numerous impressive stone walls that demonstrate the sophisticated engineering skills of Japanese castle builders during the early-modern period.
The Main Bailey
The Honmaru, or Main Bailey, occupied the highest point of Tanzaku Hill and served as the central area of the castle. A three-story, five-level castle keep with a lookout-style design is believed to have once stood here.
Today, the former Main Bailey remains one of the best viewpoints on the site. From here, visitors can see the Kumano River, Kumano Bridge, and the city of Shingu. On clear days, the view extends toward the Pacific Ocean.
The scenery becomes particularly atmospheric around sunset, when the sky, river, and distant sea are illuminated by warm evening light.
The Demaru Defensive Enclosure
The Demaru, located to the northwest of the Main Bailey, was an important defensive position used to monitor the Kumano River. A bridge is believed to have once connected this area with the Main Bailey, and traces associated with the former connection can still be identified at the site.
Kanenomaru and Matsunomaru
The areas known as Kanenomaru and Matsunomaru also formed part of the castle complex. At one point in the modern history of the site, an inn known as Ninomaru operated here, turning the former castle grounds into a popular leisure destination.
During the middle of the 20th century, a cable railway was installed on the hill. It became locally famous as the “shortest cable railway in Japan.” Although the railway is no longer operating, traces of its former route remain along the slope, offering an interesting reminder of the area’s history as a tourist attraction.
The Mizunote Waterfront Area
The Mizunote area stood along the Kumano River and included a landing place for boats. Goods were transported by water here, including Binchotan charcoal, a high-quality charcoal traditionally produced in the Kishu region.
Archaeological excavations have uncovered the remains of charcoal storage buildings, providing evidence of Shingu’s role as an important distribution center during the Edo period.
Cherry Blossoms and Spectacular Views
A Popular Springtime Destination
Today, Tanzaku Castle Park is a peaceful public space where visitors can enjoy history and nature together. From late March to early April, cherry trees come into bloom across the former castle grounds.
The combination of massive stone walls and soft pink cherry blossoms creates one of the most distinctive spring landscapes in Shingu. The contrast between the enduring stonework and the short-lived beauty of the flowers is especially appealing to photographers and visitors interested in traditional Japanese scenery.
One of Wakayama’s Best Sunset Viewpoints
The elevated position of the castle ruins also provides expansive views toward the Kumano Sea. The site has been selected as one of the Wakayama Prefecture’s “100 Best Sunrise and Sunset Views”, recognizing the beauty of its coastal scenery.
For visitors exploring the Kumano region, the castle ruins offer an opportunity to experience both historical heritage and the natural beauty of the Pacific coast from a single viewpoint.
Shingu Castle and Japanese Literature
The Poet and Writer Haruo Sato
Shingu Castle is closely associated with the literary history of the city, particularly through Haruo Sato, a poet and writer who was born in Shingu.
Sato spent part of his childhood playing around the castle ruins. His memories of the area later appeared in his literary works, including Wanpaku Jidai (The Days of Mischief). For visitors interested in Japanese literature, the castle grounds offer a fascinating opportunity to experience a place that inspired a local literary figure.
A Poem by Yosano Hiroshi
The castle site is also connected with the poet Yosano Hiroshi, better known by his literary name Tekkan. During his visit to Shingu Castle, he composed a poem inspired by the view of the Kumano coast.
The Monument to Yosano Hiroshi’s Poem
“Standing high, gazing upon the autumn sea of Kumano, who could help but shed a tear in the evening at the castle?”
The poem expresses both the beauty of the Kumano coastline and the sense of melancholy often associated with historic ruins. A monument bearing the poem can be found within the park, allowing visitors to combine historical sightseeing with a literary walk.
Preserving the Castle for Future Generations
National Historic Site and Continued Conservation
In 2003, the site was designated a National Historic Site of Japan under the name “Shingu Castle Ruins and Mizuno Family Cemetery.” In 2017, it was also selected as one of Japan’s 100 Continued Top Castles, a list recognizing important castle sites throughout the country.
Although the original castle buildings have disappeared, efforts are continuing to preserve and interpret the remains. The city of Shingu has been collecting historical photographs, architectural records, and other materials as part of plans to explore the possible wooden reconstruction of the former castle keep, watchtowers, and main gate.
These activities aim to deepen understanding of the castle’s original appearance while ensuring that its historical value can be passed on to future generations.
Historic Attractions Around Shingu Castle
Shingu Castle is located in an area rich in cultural and religious heritage. Several important destinations connected with Kumano pilgrimage culture, local history, and Japanese literature can be visited nearby.
Kumano Hayatama Taisha Grand Shrine
Kumano Hayatama Taisha is one of the three major shrines of Kumano, collectively known as the Kumano Sanzan. It is one of the most important sacred destinations in the region and a must-visit attraction for travelers exploring Shingu and the Kumano area.
Haruo Sato Memorial Museum
The Haruo Sato Memorial Museum is dedicated to the Shingu-born poet and writer Haruo Sato. His former residence was relocated and preserved as part of the museum, where visitors can discover materials related to his life and literary career, including his study.
Nishimura Isaku Memorial Museum
The Nishimura Isaku Memorial Museum preserves the former residence of Isaku Nishimura, the founder of Bunka Gakuin. The historic house is an Important Cultural Property and provides an opportunity to appreciate the elegant atmosphere of Taisho-era modern architecture.
Asuka Shrine
Asuka Shrine is a historic Shinto shrine with strong connections to the ancient religious culture of Kumano. Located near routes associated with the Kumano Kodo pilgrimage, the shrine offers another perspective on the spiritual history that has shaped Shingu for centuries.
Experience the History and Scenery of Kumano
Shingu Castle Ruins are much more than the remains of a former fortress. The site brings together the natural landscape of Kumano, the history of samurai-era Japan, the development of river transportation, and the literary culture of Shingu.
Walking beside the enormous stone walls, visitors can imagine the samurai and castle officials who once lived and worked here. At the same time, the sound of the wind moving across Tanzaku Hill and the expansive view toward the Kumano River and Pacific Ocean create a peaceful atmosphere that is very different from the bustle of modern city life.
For travelers interested in Japanese castles, history, nature, architecture, or literature, Shingu Castle Ruins are an especially rewarding destination in the Kumano region. A visit becomes even more meaningful when combined with nearby sacred sites such as Kumano Hayatama Taisha and the historic streets of Shingu.
Whether you visit during the cherry blossom season, at sunset, or on a clear day when the river and sea stretch toward the horizon, Tanzaku Castle Park offers a memorable way to experience the enduring connection between Kumano’s history and its spectacular natural landscape.