This paper clarified the idea of 2 story house in modern Japan by using the discourse of 63 housing books published from the late Meiji to early Showa periods.
From the previous research it is thought that functional differentiation of floor plan promoted 2nd floor planning. Therefore, this research focused on the change of the "Ima" of the 1st floor at the time. "Ima" conventionally had the function as a private room, but also included various functions such as accompanying functions of sleeping and talking with visitors. Eventually, "Ima" shifted to a public room function western living room, we assumed that the establishment of functions of each other room was promoted and led to two stories planning. We analyzed how changes in the function of the "Ima" and that arrangement method affect the discourse of the arrangement method to 2nd floor of the drawing rooms" and the bedrooms.
At the first, we confirmed that “Ima” changed its function as a public room in early Taisho era, and the discourse changed so that it was placed on the south side of the plan. In addition, around the time of the late of Taisho periods, the proposal of the ”Ima” which became a Western-style room appeared. In this way the “Ima” got priority than the drawing rooms. So the discourses of the drawing rooms arranged on 2nd floor were described in middle of Taisho period intensively. From the above, we considered that the idea appeared about the changing arrangement of the drawing rooms to the 2nd floor to secure a space for the “Ima”.
On the other hand, the discourses of bedroom's arrangement on 2nd floor did not formed smoothly than the drawing rooms it. It seems that the main factor was due to could not set up wet area on 2nd floor by municipal wastewater undeveloped at that time in Japan; It was difficult to put in bathroom around the bedroom like a western housing sleeping space. However, the discourses of arranging to the bedroom at 2nd floor were also appeared in early Showa period. It seems that the major factor were the idea of the western style's the Ima (sitting on chairs, that means the living room) spread among the architects, on contrarily the idea of traditional sleeping style on tatami were reduced. Also, we confirmed that there were some discourses attempt to cope with towards the problem of municipal wastewater.
The discourses regarding the drawing room's arrangement on 2nd floor were caused from only a solution for the plan of the relationship between the Ima. In contrast, the discourses regarding the bedroom's arrangement on 2nd floor were caused from to the primary purpose to establish the sleeping space in the Japanese houses. It were consistent to arrange on 2nd floor.
We considered that the discourses related to the bedroom arrangement at early Showa period leading to aspects of the the 2nd floor of the modern housing. In other words, It means that the planning idea of the 2 story houses had already begun to formed from this period. Also, from the housing books at the time, we could find that the attempt of the architects to clearly define the role of the living room changing from the traditional room concept (which allowed the inclusion of various functions).
