- Mitsui Real Estate + YAMASHITA Architectual Office
- Kajima Corporation, Mitsui Construction Co.
- This building earns its honor as the first skyscraper built in Japan. The major revision of the Uniform Building Codes of Japan in 1963, which effectively removed the regulations limiting building heights, and the approval in the following year for the application of the Specified Blocks System, together, laid the ground for the realization of this skyscraper project. The design presented a unit based on an ergonomically derived dimension of 3.2mx3.2m as the guiding module for establishing a spatially comfortable human scale in offices, and utilized this module to uniformly standardize the building in its entirety.
- 1968年（改修増築 2009年）