Type: Mixed Use
Developer: Mitsui & Co. Ltd., Mitsui Fudosan Co. Ltd.
Owner: Mitsui & Co. Ltd., Mitsui Fudosan Co. Ltd.
Design Architects: Skidmore, Owings & Merrill, KMDW
Architects: Nikken Sekkei Ltd., Kajima Corp.
Site Size: 5.16 acres (2.1 ha)
Date Opened: February 1, 2020
Date Completed: December 1, 2022
Buildings: 127,600 square feet (11,855 sq m)
Parking Spaces: 357
Open Space: 97,360 square feet (9,045 sq m)
Otemachi One, the largest mixed-use development in Tokyo’s Otemachi District, combines offices, shops, event venues, a luxury hotel, and expansive public green space at the threshold of Tokyo’s Imperial Palace. The development occupies a prime site that was previously home to three office buildings, including Mitsui & Co.’s former headquarters.
Otemachi One’s two towers honor Tokyo’s historical context and reflects its future as a global innovation center. Mitsui & Co.’s new headquarters occupies the shorter, 525-foot (160 m) tower, which faces the Imperial Palace and pays homage to the historic building in style, materials, and scale. The design draws inspiration from traditional Japanese joinery and woodworking techniques, reinterpreted in masonry and glass.
The taller tower, 656 feet (200 m), is oriented toward the central business district and has glass and steel facades intended to embody contemporary Japan. This 40-story tower accommodates additional office space as well as the seven-story Four Seasons Hotel at the top.
Creating meaningful public spaces was a crucial part of the design. Otemachi One’s garden is one of the largest green spaces in the area and covers 64,580 square feet (6,000 sq m). It houses an existing historical monument, the Masakado Shrine, and is landscaped with native plants, reflecting pools, and venues for outdoor programming.
Below ground, a corridor dubbed Otemachi One Avenue links directly to Tokyo Metro and is lined with shops, restaurants, and health and wellness services. A grand atrium staircase floods the corridor with natural light and brings elements of greenery below grade, enhancing the pedestrian experience.
Both towers incorporate sustainable strategies, including cavity walls, ventilated mullions, energy-efficient glazing, a high-performance building envelope, a kitchen wastewater treatment system, stormwater filtration, solar power, and automated systems for lighting and window blinds. In the basement is a new, high-efficiency district heating and cooling plant that serves 9.9 acres (4 ha) of the Otemachi area. Supplemental energy comes from a gas-powered cogeneration system as well as reused waste heat and gray water heat. In earthquake-prone Tokyo, Otemachi One prioritized safety with state-of-the-art seismic damping structures. The towers received an honorable mention in the 2023 American Institute of Architects Japan Awards.
Since its completion, Otemachi One has achieved strong market acceptance, with office spaces almost entirely leased to global firms such as Mitsui & Co., Dell, PwC, UBS, and SAP. The Four Seasons Hotel has one of the highest occupancy rates among Tokyo’s luxury accommodations.
Otemachi One showcases how large-scale urban development can successfully integrate diverse uses while respecting historical context. By creating meaningful connections between transportation, public space, and a variety of amenities accessible day and night, the project sets a new standard for mixed-use development in dense urban areas.
