The building is a combined headquarters for the Dai-Ichi/Seimei Insurance Company and the Norinchukin Bank. The new building consists of two reconstructed historic structures and a new 900,000 square foot tower, which is 20 stories high. The existing Dai Ichi-Seimei building is a landmark of modern architecture, and the Norinchukin Bank is a refined and elegant design in the Classic Showa manner. The buildings stand on Hibiza moat, facing the Imperial Palace in Central Tokyo. Approximately half of the site has been preserved. The project is Japan's first application of a Special Planning Permission for historic building conservation.

In approaching the problem of adding a substantial volume to the combined sites of both buildings, preservation was a primary objective; preservation not only in the sense of saving the facades but also in the sense of ensuring that the addition did not detract from their character. In order to develop the required additional area, it was necessary to demolish the Norinchukin Bank. The Dai Ichi-Seimei Building was retained because of its landmark status - it was the WWII Japanese Army Headquarters and, later, served as the headquarters of General MacArthur after the war.

The building is seen mostly from the Imperial Palace grounds and surrounding parks and roads. This combined building, while providing additional space for both owners and giving them equal identity on the site, also constitutes a handsome and appropriate addition to the environs of the Imperial Palace.