The purpose of this study is to clarify how "Interspace" was reflected in the proposed drawings and planned as part of the plan configuration in the major design competitions of the time in the Taisho era, when foreign spatial concepts such as balconies and terraces were imported into Japan by Westernization.
In the design competitions of 1915, most of the proposals often consisted of a continuation room on the south side and a kitchen or tea room on the north side. However, most of the proposals had no corridors, and the floor plan was designed to be customer-focused, with a veranda around the perimeter to connect plumbing spaces such as lavatories and bathrooms so that the family's traffic line did not overlap with the guest's traffic line. Therefore, the curbside, which is a semi-outdoor space, had a corridor-like character to secure the movement line function within the house.
In the design competition in 1916, many Japanese style houses had a "middle corridor type" with a central interior corridor. At this time, although the veranda in many of the proposals had lost their circulation function, the space was still attached to the rooms on the south side, and had been transformed into a space that had the character of Hare; noticeably cheerful and formal places.
In the design competitions in 1919 and 1921, there was a rapid increase in the number of proposals that mimicked Western-style houses, and many proposals were for two-story buildings. Thus, a hall with a staircase appears, and the floor plan form that accesses the various rooms from that hall increases. At the same time, we were able to identify a number of Interspaces, such as balconies and terraces, which were deeper than the curbs, and which were assumed to contain furniture that could not be passed through.
At the Heiwa Housing Expo in 1922, which was held in accordance with the "Six Ambitions for Housing Improvement" announced by the Life Improvement League in 1920, all houses were unified into a seated style. The corridor, which causes an increase in floor space, was considered uneconomical, and in order to make the floor plan extremely compact, many proposals were made for a living room-centered floor plan, in which each room is almost like a continuous one room. This living room-centered floor plan was a manifestation of a cultural housing style in which the family's life was the center of attention, but there were few proposals that included "Interspace" because “Interspace” increase the floor areas.
The rational, minimalist, living room-centered floor plan was not very popular. Instead, at the later Kaizo Housing Expo in 1922, while many of the middle corridor and hall types appeared, the living room, the center of family life, tended to remain the largest space compared to the other rooms. In addition, living room-centered floor plan was still maintained, and “Interspace” such as balconies and terraces, which have a residual character, appeared again in the form of continuity with the living room as the center of the house.
