Bitchu Matsuyama Castle sits majestically near the peak of Gagyuzan moutan. The castle in the sky, as it’s lovingly known, is part of the distinguished clique of just 12 castles with an existing castle tower from the Edo period, and of these, it sits alone as the only remaining mountain castle in Japan.

The castle keep, double turrets, and part of the earthen walls were built in the Edo period.
It is designated as a National Important Cultural Property.

floating in a sea of clouds

buchu matsuyama castle in the sky

Bitchu Matsuyama Castle could be from a dream or Miyazaki film and has amazed visitors for centuries with its unique mountain castle construction and location.

The castle construction, which skillfully utilizes granite and timber quarried from Gagyu Mountain, is well worth a visit. In addition to the castle tower, which is designated as a National Important Cultural Property, the double turrets, and earthen walls, there are many other sights to see.

Get to know Bicchu Matsuyama Castle in depth.

The history of Bichu Matsuyama Castle dates back to the Kamakura period (1185-1333), when a fort was built on Omatsuyama.

Bichu Matsuyama Castle in fall

Over time, Bitchu Matsuyama Castle was shifted from Omatsuyama to Komatsuyama before taking its present form. With numerous changes of castle lords, the castle flourished as the focal point of Bicchu through to the dramatic finale of the Edo period.

How To View Bitchu Matsuyama Castle from the Sea of Clouds Observatory

The sight of Bitchu Matsuyama Castle, apparently floating in an expansive sea of clouds, is nothing short of fantastic. It is called the “mountain castle in the sky” when shrouded in mist and experiencing it in perfect conditions as a majestic experience.

Unkai Observatory Information

If you want to view the mountain castle in the sky or perhaps take a jaw-dropping photo, the best viewing point is the Sea of Clouds Observatory. Time to put those hiking shoes on.

When can I see the sea of clouds phenomenon?

From around the 15thof September to spring in early April, from the break of dawn to about 8:00 a.m.

The absolute best time to view the thick morning fog is early morning from the end of October to the start of December.

The morning when it is warm during the day and cool at night or early in the morning, with a large temperature difference. The rate of appearance increases on days when the weather forecast calls for clear skies.

If it’s raining, you will be out of luck. However, some say that the majestical fog often is at its best early in the morning, on the following two or three days after rain.

Getting To The Unkai Observation Deck

The Sea of Clouds Observatory is in a different area from the main castle keep.

There is a possibility of encountering wild monkeys (designated as a national natural treasure) around the observatory.

If you see a monkey, it’s best to act calmly and don’t get the little guys too excited.

Be careful of snow during the winter from December to late February.

Bitchu Matsuyama Castle Castle Walking Highlights

Introducing points to enjoy walking to Bitchu Matsuyama Castle to experience history and nature.

Castle Ruins Points of Interest to the Castle


The ruins of Aihata Kidoto, are said to be the site of an old battlefield from the Bicchu War of 1574. A well and other remains can still be seen.


A shine on the tallest peak of Gagyuzan (480m) was built in modern times, but there is an excavation where you can find the remains of the original shrine.

Ruins of Omatsuyama Castle

This is the site of the beginning of Bicchu Matsuyama Castle, where Akiba Saburo Shigenobu built a fortress in 1240. The ruins of the medieval fort still remain.


This man-made pond is the largest castle water reservoir in Japan. It is said to have been used to wash people’s heads and swords during battles and is also called “Blood Pond” or “Head Washing Pond.

Suspension Bridge

The suspension bridge is located 730 meters from the keep, about a 30-minute walk. You can cross the bridge as if you were taking a walk in the air.

The Dramatic History Of Bitchu Matsuyama Castle

Bitchu Matsuyama Castle has been built on Gagyuzan Mountain since the Kamakura period (1185-1333).
The castle’s history, which has developed under the hands of generations of castle lords, is presented here from a variety of perspectives.

The sole surviving mountain castle in Japan

Bitchu Matsuyama Castle is perched on Gagyuzan Mountain, about 480 meters above sea level, at the northern edge of Takahashi City.
Among the 12 castles in Japan, Bitchu Matsuyama Castle is the only one in the form of a mountain castle and is widely known as Japan’s only surviving mountain castle.

The wooden castle tower, the double turrets, and part of the earthen walls still exist, and were designated as National Important Cultural Properties in 1941.
The Honmaru South Gate, East Gate, Udegi Gate, Roji Gate, Five Flat Yagura, Six Flat Yagura, and earthen walls were reconstructed in 1997. The damaged keep was repaired in 2003 to preserve the original appearance.

Oshiroyama” in the shape of a cow

Gagyuzan, affectionately known as “Oshiroyama” by Takahashi citizens.
Gagyuzan comprises four peaks from the north: Oomatsuyama, Tenjin-no-maru, Komatsuyama, and Maeyama.

The name “Gagyuzan” or “Mt. Gagyufusozan” comes from its resemblance to an old cow lying in the grass when viewed from the west.

In the Kamakura era (1185-1333), a fort was put up on a northern peak of Gagyuzan, and over time, the fort spread to the whole of the Gagyuzan area.
Komatsu (about 430 meters above sea level) is now commonly referred to as “Bitchu Matsuyama Castle.
Throughout its long history, the castle’s function has changed from being a medieval castle for warfare to a more modern castle equipped with a keep and a stone wall”.

During the Age of Warring States, the whole mountain became a large-scale fortress.

The story of Bitchu Matsuyama Castle begins in the Kamakura era (1185-1333). In 1240 (En’ou 2), Akiba Saburo Shigenobu, who was appointed as the local governor of Yuhan-go (present-day Yuhan-cho, Takahashi City), built a fort on Mt.

Later, the castle’s center was moved to the summit of Mt. Komatsu, and the castle’s layout changed with the times. During the “Bitchu War” of 1574, it is estimated that 21 fortifications were erected in the area around Gagyu Mountain.

The castle’s lord and protector while the war was raging was Mimura Motochika. The Mimura clan had knotted together a sprawling fortress that covered the Gagyuzan area in full. Still, the castle itself fell during a relentless siege of possibly up to 80,000 soldiers of the powerful Mori clan.

In 1575, Terumoto Mori replaced the Mimura clan as castle overlords. Bitchu Matsuyama Castle became the base for the Mori clan’s ambitious advance east. It wasn’t long before a power struggle with the rising force of the Oda clan unfolded in Bitchu.

After the Mori clan found themselves on the losing side, once the dust settled at the Battle of Sekigahara, they retreated to the two provinces of Hochou in the Edo period. Bitchu Matsuyama Castle was then repaired and reconstructed by Masatsugu Kobori and Masakazu (Enshu), a father and son appointed as magistrates of Bitchu province.

Once the dramatic Battle of Sekigahara was over, in 1600, Bitchu Matsuyama Castle came under the jurisdiction and ownership of the now dominant Tokugawa Shogunate.

By order of the shogunate, father and son Masatsugu Kobori and Masakazu (Enshu) were assigned as magistrates.

Enshu, who was reportedly a renowned castle builder, built a camp (onekoya) at the entrance to the mountain and began renovations to the castle itself.

He was also apparently a bit of a green thumb. He created a garden at Yorikyuji Temple, which he used as a temporary residence to conduct government affairs after the castle was razed to the ground during the Bitchu War.

Tsurukame no Niwa,” listed as a national place of scenic beauty, is a Zen-in style karesansui Horai (dry landscape garden).

With Atagoyama (Mt. Atago) as a borrowed landscape, white sand is used to represent ocean waves, and stone arrangements of crane and turtle islands are placed in the garden.

The large cutouts of azalea trees representing rolling ocean waves are also magnificent.

Reign of Mizutani’s Three Generations

In 1642, Katsutaka Mizutani got his promotion and became the castle’s lord, after serving in the Naruha clan from Shimodate in Hitachi. He put his head down and devoted himself to establishing the clan government, including developing the Takase boat route and the Tamashima rice paddies. His son, Katsumune, worked on the construction of the Takase Passage, and from 1681 to 1682, he undertook a major reconstruction of Bitchu

Matsuyama Castle.

The castle’s entire structure was completed, including the main citadel, double turrets, and the Ote-mon Gate. The castle tower, the double turrets, and the east earthen wall of the Sanpei-yagura were added during this construction phase.

The Mizutani clan was given the keys to the castle in 1642, and although they are credited with repairing much of the castle, the clan ceased to exist after three generations due to a lack of heirs.

In 1694, the Asano clan of Banshu-Ako next took charge of the castle. Oishi Kuranosuke, known for his work on “Chushingura,” took over the mountain top fortress from the severed Mizutani family.

Saved from financial ruin: Yamada Houya’s Domain Reforms

Katsushizue Itakura, lord of the Bicchu-Matsuyama domain, helped Yoshinobu Tokugawa during the dramatic conclusion of the Edo period. Yamada Hokoku, a scholar, serving under Katsusei, decisively reformed the domain government and saved it from the brink of financial ruin.

In 1850, the Bicchu-Matsuyama domain was 100,000 ryo (about 30 billion yen in today’s currency) in debt.

Hoya, then aged 46, implemented a policy of “up-and-down thrift,” in which everyone from the samurai to the common people saved money, as well as debt reduction, industrial promotion, and the renewal of the clan’s currency. In under a decade, his austerity program had reduced the debt to zero and left behind an accumulated wealth of 100,000 ryo.

Along with bean-counting, Hoya was also an esteemed educator, teaching many young people at the domain school Yuseikan, a private school he established, and after the Meiji period, at the Shizutani Shosha (present-day Kanya Gakko) in Bizen (Bizen City). Hoya’s outlook and reforms, not to mention the unity he had fostered, were appreciated as a great legacy to the next generation.

Opening of the Castle and the Decree to Abolish the Castle

In 1868, the Boshin War kicked off, in which the Tokugawa shogunate and the new Meiji government forces, including the Satsuma and Choshu clans, fought.

The Itakura clan, which had been serving as the top-level retainer of the Edo shogunate, was regarded as an enemy of the emperor and imperial court, and the Bicchu-Matsuyama clan found itself in dire straights.

Yamada Houya and others knew which way the wind was blowing and made the call to unlock the castle gates and hand the keys to the newly formed government forces, saying, “We have no other choice but to prevent a reckless battle and ensure the clan’s survival. This decision saved the castle.

In 1873, an ordinance was issued to abolish castles, and many castles across Japan sadly had their keepers and buildings demolished. The Bicchu-Matsuyama clan was unfortunately not left off the hook, and the Onekoya (residence of the lord) at the base of the mountain was torn down, and a local high school was built on its foundations.

However, the castle tower, turrets, and gates were fortunately located on the inconvenient mountain top, and were left intact for future generations.

The Reconstruction Of Bitchu Matsuyama Castle

As time passed through the Meiji, Taisho, and Showa eras, the turrets of Bitchu Matsuyama Castle were damaged and in disrepair.

During the early years of the Showa period, the castle was close to collapsing into rubble but was saved by history teacher Tomoharu Nobuno, in Takahashi. Knowing the historical importance of the building, Nobuno repeatedly pulled on his hiking shoes and accended to survey the site. He collected detailed architectural records of the structure keep and published “Bicchu Matsuyama Castle and its surroundings” (Bicchu Matsuyama Shiro to Qishiroshita).

This book inspired residents to form the Takahashi Hosho-kai, a group dedicated to restoring the castle.

In 1939, the main keep was dismantled, and the earthen walls were repaired as part of the “Showa Era Repairs. Local school students carried an impressive 20,000 tiles up to the mountaintop site to help out during the reconstruction.

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