Third Floor
(1) The Floor without Windows
The third floor of the Great Keep, also called the “hidden floor” or “dark floor,” is concealed within the frame of the second-floor roof. The third floor of the Inui Keep is built in a similar fashion.
While the exact purpose of this floor is unknown, it may have been used for storage. Many of the pillars and beams on the third floor have been roughly finished with an adze, creating a pattern that resembles seashells or fish scales.
Given the low height of the ceiling, it is possible to see the small wooden slats that were added to cover the gaps between the wooden planks. These slats were intended to provide additional strength to the ceiling and prevent it from warping.
An opening in one corner provides quick access to the fourth floor, but its purpose is a mystery.
Fourth Floor
(1) Castle Lord’s Sitting Room
It is thought that the largest room on the fourth floor would have served as temporary quarters for the castle lord during a siege. Compared to the lower floors, the ceilings here are higher, and lavish materials were used to furnish it, such as Japanese cypress timbers for the pillars. The lord’s quarters are partitioned off from the rest of the floor using thin bamboo blinds hung from the lintels.
(2) Steepest Staircase in the Castle
The fourth floor reaches a height of just over 4 meters from floor to ceiling. Since the staircase is placed in a bay between two pillars, it was built at the incredibly steep angle of 61° to accommodate the high ceiling.
In comparison, the staircase on the fifth floor is two bays long and has a short landing in the middle. The fifth floor is around 40 centimeters taller than the fourth floor, which makes its staircase very steep. The landing was added to reduce the risk of a long fall, and the stairs were built across two bays to accommodate it.
Fifth Floor
(1) Council Room
The fifth floor of the Great Keep may have been used as a council room during an attack on the castle. The latticed windows and openings in the roof gables would have allowed generals to look out in all directions over the castle compound. The alcoves on this floor are actually located behind the large gables of the roof.
(2) Pillar Indentations
By the turn of the twentieth century, Matsumoto Castle had fallen into disrepair and had begun to lean. Fearing that the castle would collapse, Kobayashi Unari (1855–1914), the principal of the local middle school, helped establish the Matsumoto Castle Preservation Society in 1901. Repairs to the castle began in 1903 and were finally completed in 1913. According to legend, the workers straightened the Great Keep by hoisting it upright with ropes. Indentations possibly caused by these ropes can be seen on one of the pillars on the north side of the fifth floor.
Reports prepared during the large-scale dismantling and reconstruction of the castle in the 1950s posit that a different method was used: the Great Keep was likely leveled by strategically reducing the length of certain pillars.