Otemachi One

A large-scale mixed-use development completed in February 2020 in the heart of Otemachi, comprising a 40-story, approximately 200-meter tower and the Mitsui Bussan Building. Developed by Mitsui & Co. and Mitsui Fudosan, with SOM as design architect, it stacks offices, a hotel, a hall, and retail into a single urban block.

Use

Office tower

Area

Chiyoda City

Completed

2020

Floors

40 above ground, 5 below

Height

200 m

Developer

Mitsui & Co. / Mitsui Fudosan

Architect

Nikken Sekkei / Kajima Design (joint venture); SOM (design architect)

A Twin-Tower Complex at the Heart of Otemachi

Otemachi One is a large-scale mixed-use development completed in February 2020 in Chiyoda City’s Otemachi 1-chome district. The complex comprises two buildings: the main tower, standing approximately 40 stories and 200 meters tall with five basement levels, and the Mitsui Bussan Building, a 30-story structure rising to around 160 meters. Developed by Mitsui & Co. and Mitsui Fudosan, the design was handled by a joint venture of Nikken Sekkei and Kajima, with Skidmore, Owings & Merrill (SOM) serving as design architect.

Otemachi 1-chome has long been a staging ground for Tokyo’s celebrated chain-type redevelopment. The JA Building (2009) and Otemachi Tower (2014) stand nearby as earlier links in that chain, and Otemachi One represents the newest and largest milestone yet. With the Tokiwabashi area redevelopment gathering pace just to the north, the completion of this complex marks both an endpoint and a handoff to the next phase of the district’s transformation.

Stacking Hotel, Hall, and Office on One Axis

For decades, Otemachi’s skyscrapers were built almost exclusively as pure office blocks. Otemachi One signals a deliberate shift: the tower’s upper floors house a hotel, while a large-capacity multipurpose hall sits within the shared facilities — layering accommodation, events, and business into a single vertical structure. Norinchukin Bank underscored the complex’s appeal when it relocated its headquarters from the nearby JA Building to the tower in 2022.

SOM’s facade design uses a horizontal-banded curtain wall that softens the visual impact of the roughly 200-meter volume against the measured scale of the surrounding Otemachi streetscape. At ground level, open plazas and a low-rise commercial zone wrap the complex, creating pockets of daylight and movement within one of Tokyo’s densest business districts.

Summary

Otemachi One, completed in 2020, anchors a major urban block in Chiyoda’s Otemachi district with a 40-story, roughly 200-meter tower alongside the Mitsui Bussan Building. The project’s stacking of offices, hotel, and hall — shaped by SOM’s clean-lined design — offers a benchmark for what a contemporary mixed-use tower in central Tokyo can achieve. Walking the open plazas at its base alongside the JA Building and Otemachi Tower brings the sequential logic of the area’s chain-type redevelopment vividly into view.

Related articles: JA Building / Otemachi Tower / Otemachi Place

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