Building No. 21 (1914-1961) [From tenement houses to the prototype of large-scale office buildings]

Building 21, which stood in the current Shin Tokyo Building block at roughly one-quarter the size of the original, was designed by Yasuoka Katsuya. Building 13 marked the completion of the brick-built office buildings of the 1st Block London complex, and from Building 14 onwards, even as the main structure changed to reinforced concrete, the building continued to follow the tenement-style floor plan. Building 21 adopted a large-room floor plan similar to current rental office buildings, with each tenant sharing an entrance hall (floor plan: "octagonal hall"), staircases, and toilets, and facade also changed from a single window style to a series of large, continuous openings reminiscent of horizontally extending windows, in response to the horizontally expanding office space. However, the plan clearly stated that brick would be used for the finish, suggesting an intention to harmonize with the 1st Block London streetscape and create a town as a whole. Furthermore, in the 331st issue of Architectural Magazine, which reported on the completion of the building, it was stated that "the costs of spot cleaning in the corridors, water charges, cleaning the floor and elevators, etc., were the responsibility of the lessor." This suggests that Building 21 not only embodies the prototype of today's large-scale office buildings, but also the philosophy behind building management.