General Information

The large and main keeps of Kumamoto Castle stand side by side. Both were burnt down by fire before the opening of the Seinan War in 1877, but they were rebuilt with concrete construction in 1960. The Kumamoto Earthquakes in 2018 caused some damage, such as the fall of roof tiles and Shachihoko-shaped tiles from the top floor, and the destruction of the stone walls of the basement room. As a symbol of the restoration project, the main keeps were a top priority, and they were completely restored in 2021. The large main keep has three layers on the outside, six floors, and one basement inside. From the top floor, you can enjoy views of Kumamoto City and the distant Aso mountains. More about Japanese Castles , Click here.

Kumamoto Castle was built by Kato Kiyomasa, known as the god of civil engineering.

The entire area of the castle is 980,000 square meters, almost twenty-one times larger than Tokyo Dome. The circumference is 5.8 km long. It is one of the largest castles ever built in Japan. It is often chosen as one of the three greatest castles (along with Edo Castle and Osaka Castle).

Kumamoto Castle was thoroughly designed to withstand any attack, no matter how strong or how long, making it impregnable.

It is especially known for its beautifully curved stone walls named “Mushagaeshi.”

The Founder, Kato Kiyomasa

Kato Kiyomasa also had the common name Toranosuke. He is respectfully called “Seisho-kou” (kou is similar to Mr.) by the people of Kumamoto. This is largely because he developed new rice fields and controlled river flow to prevent floods for the sake of his people.

He greatly helped win various battles as a subordinate samurai for Toyotomi Hideyoshi and was eventually appointed as the lord of Higo Province. During the Korean Invasion, he was assigned to build castles and learned more about building skills.

The statue of Kiyomasa looks brave and daring. However, the portrait of Kiyomasa drawn right after his death looks very sensitive and cowardly. If he was weak and afraid of death, it makes sense why he tried to build an unbeatable castle.

The Main Towers (Keeps)

The features of the main keeps are the unique style of construction with Chidori-hafu (triangular-shaped small roof) on all four sides and Kara-hafu (the attached small roof curved upward in the center) on the top floor. The rooms were named after the type of weapon stored, such as rifles, armor, bows, and others. You can see the iron spikes called “shinobigaeshi” on the stone walls to prevent enemies from invading. The castle contains many defense devices.

Its Defensive Structure

Kumamoto Castle has many devices to protect itself perfectly from enemies, which is considered excessive, but this is largely due to Kato Kiyomasa’s caution.

Masugata Koguchi

The first barrier enemy warriors face is the entrance space called “Masugata Koguchi.” This is a square-shaped path space surrounded by walls on all four sides. The walls have holes called “Sama” through which bullets or arrows can be shot. Thus, enemy warriors can be shot from all directions.

Takenomaru

The next barrier is the open space called “Takenomaru,” surrounded by high walls lined with Yagura, or turrets, to shoot the enemies who reach this space. It is said that there used to be 66 Yagura in Kumamoto Castle.

The third barrier is a double pathway. One path leads to a dead-end, while the other goes through six Masugata Koguchi corners, open to shots from all directions.

Yagura: The Japanese term “yagura” literally means a storehouse (kura) for arrows (ya), but they were used to store all manner of weapons, food, and supplies. Yagura were not just storehouses; they were also vital defensive platforms and lookout towers placed at strategic locations throughout the castle.

Kuragari Gomon

The last barrier is the gate called “Kuragari Gomon” (Passage of Darkness) leading to the main keep. This underground gateway is dark enough to blind enemy warriors as they pass through, leaving them unprotected.

Facing the South

These defensive structures of Kumamoto Castle face south because it faces Satsuma Province, which Kato Kiyomasa feared the most. It is said that Kato Kiyomasa made a small escape tunnel at the bottom of a small castle tower in the northern area.

Key Structures

Honmaru, Ninomaru, Sannomaru

Honmaru is where the master of the castle is to plan a strategy.

Ninomaru is where the master’s family and the servants reside.(Samurai residence)

Sannomaru is the front of the battle against the enemy. On-site commanders and elite forces fight against the enemy. 

Takenomaru

Takenomaru is the southern defense line, featuring the long wall called “Nagabei,” which is 242 meters long.

Iidamaru 5 storied castle tower

Iidamaru’s five-story castle tower was damaged by the earthquake in 2016 and was barely supported by a single remaining stone pillar.

Sukiyamaru

Sukiyamaru Hall is considered to have been used for cultural activities such as tea ceremonies, Noh plays, and poetry readings. It was monitored from the building to the south, which has holes for gunfire and stone-throwing.

Heizaemonmaru

Heizaemonmaru is located in the western area of the main keep. Originally, four castle towers existed, but now only one, “Udoyagura,” remains. Udoyagura is called the third main keep because of its large structure next to the main keeps.

This Uto-Yagura is the only layered tower that retains its original style in the foundation. Three-layered with five floors and one basement, it is equal in scale to the other main keeps and is called “the Third Main Keep.” Until the beginning of the Meiji Era, there were four other five-layered towers in the castle. It is said that it was named Uto because samurai from the castle of Uto, a sub-territory of Higo han, now Kumamoto, were stationed near the tower.

Defense Devices

Shinobikaeshi

Shinobikaeshi refers to a fence designed to prevent samurai warriors or ninjas from climbing up to the castle tower.

Musyakaeshi

Mushakaeshi refers to sharply sloped stone walls that no warrior or ninja can climb up to reach the castle tower.

Ishiotoshi

Ishiotoshi refers to holes from which stones can be dropped to attack enemies trying to climb up the castle walls.

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