from：松本市教育委員会松本城管理事務所編『国宝　松本城』

Inner Structure of Matsumoto Castle

Though Matsumoto Castle's main tower has a outlook of 5 storied shape, it has 6 strata in its inner structure.
The castle is the oldest one that was build in the type of Tower-Stairing in the early modern age. However it keeps partly the framework of Watcing-Tower type in its inner structure, then it is of the transitional architecture.
Inside of a large triangular gable between the tird and the fourth storey, stair-frame of semi Watching-Tower style is built in. That is the structure in which a watching tower is placed opon the gambrel-frame. The structure is of Watching-Tower type. The purpose of its top stair, where general commanders and staffs would meet together, was that they would get the widest perspective to consider the situation and make decisions for battle.
It was a wathcing tower in such a context. The top stair was a headqarter.
Under the architectural mode, a main tower was shaped by piling up similar stratum-frames.
Just beneath the top stair, the fourth stair, which has a high ceiling, is the room for their lord who would be protected by the loyal guard. The form of it is Shoin style.
Beneath them are stairs which have a complicated structure.
In subordinate three storeis, a frame of four stairs is inserted because they keep a place, hidden from outside, in which many soldiers would meet together. They could avoid shots from outside.
It was called Musha-Damari in Japanese. Musha means Samurai-soldiers and Damari(Tamari) means a room for aggregation.
On the wall of the lowest stair was attached Ishi-otoshi, i.e. the stone-fall-place, where they would throw down heavy stones or lances against their enemies rushing up the stone walls.
It is said that the early modern type of the castle was originated by Oda Nobunaga. He built Azuchi Castle in Watching-Tower style with the huge stone-walled banks first. The mainest purpose of that was to show his authority and power, by stacking the graceful watching tower on the great gable-roof.
He would like to look down around the circumstance from there, feeling his superiority. He thought that he had established so strong hegemony all over Japan that any war-lord could not attack him. Then he scarecely recognized risk of being rebelled.
However the mentality of the war age had not ended. The warfares continued for 25 years thereafter. In those days the architecture of castles was innovated for warfares and domination into Tower-Stairing type.