Mitsui Main Building

A Headquarters Reborn from the Ashes of the Great Kanto Earthquake

The story of the present Mitsui Main Building begins with destruction. The previous head office on this site, designed by Yokogawa Tamisuke and completed in 1902, survived the shaking of the 1923 Great Kanto Earthquake structurally intact but suffered devastating fire damage from the surrounding inferno. The Mitsui partnership debated whether to repair or rebuild. In the end, with operations expanding rapidly and a national mood that demanded leadership in reconstruction, the decision was made to demolish the old building entirely and erect something altogether more ambitious.

President Mitsui Hachirouemon Takakimi reportedly issued a striking instruction: the new headquarters must be able to withstand an earthquake twice as powerful as the one that had just struck Tokyo. Managing Director Dan Takuma, who had cultivated extensive American business and engineering contacts during a 1910 tour of the West, took charge of realizing this vision. He commissioned the New York firm of Trowbridge & Livingston—at the time among the three leading architectural offices in that city—to design the building, and engaged the James Stewart Company, also based in New York, to handle construction. Trowbridge & Livingston had previously designed Pittsburgh's Mellon Bank, the very institution Dan had taken as a model. Construction began in 1926 and the new Mitsui Main Building was completed on March 23, 1929, opening for business that June.

Three Words Carved in Stone: Grandeur, Dignity, Simplicity

Dan Takuma defined the building's design philosophy with three English words: Grandeur, Dignity, and Simplicity. Every choice—from the proportions of the colonnade to the calm restraint of the carved ornament—was meant to embody those ideals. The result is a confident essay in American Beaux-Arts neoclassicism, a style that was already passing out of fashion in the United States but that perfectly suited the institutional weight of a great financial house.

The structure is a steel-framed reinforced concrete building with five visible stories above ground (effectively seven, because a continuous mezzanine runs the length of the first floor) and two basement levels. It is rectangular in plan, stretching east to west and presenting three monumental facades to the surrounding streets—Chuo-dori to the east, Nichigin-dori to the west, and Edo-zakura-dori to the south. The walls are clad in pale Inada granite from Ibaraki Prefecture, lending the building its characteristic luminous gray tone.

What dominates the design, however, is the colossal Corinthian order. A continuous rhythm of fluted columns and paired pilasters runs across all three street facades, supporting a heavy entablature crowned by a deep cornice. Above the colonnade, the upper stories step back to lighten the visual mass. Twelve relief panels—four on each main facade—symbolize the diverse activities and values of the various Mitsui companies that once filled the building: banking, mining, trading, trust services, and more.

Inside: Marble Halls, a 50-Ton Vault, and a Ship Across the Sumida

Step through the main entrance and the building's interior reveals an even more theatrical sense of occasion. The first-floor banking hall is a vast, double-height space punctuated by enormous marble Doric columns. Italian marble was used lavishly for floors, columns, and wall surfaces; the ceilings and beams carry refined classical ornament. The original counters, fittings, customer benches and stone furniture installed for the Mitsui Bank and Mitsui Trust offices are themselves protected as part of the cultural property designation, an unusual and valuable level of preservation.

Engineering ambition matched architectural ambition. The building was equipped with full air conditioning—rare anywhere in 1929—and with a system of pneumatic tubes for moving documents between floors. The most legendary feature is the great circular vault door of the Mitsui Bank's basement strongroom. Manufactured by the Mosler Safe Company of the United States, the door measures roughly 2.5 meters in diameter, is 55 centimeters thick, and weighs about 50 tons. Because the wooden Nihonbashi bridge could not bear such a load, the vault door was shipped up the river by barge, unloaded near Shin-Tokiwabashi, and hauled to the site through the streets in the dead of night.

A Witness to the Twentieth Century

The Mitsui Main Building has stood at the center of Japan's modern history. In March 1932, just three years after the building opened, Dan Takuma—the very man who had commissioned it—was assassinated at the front entrance by a member of the ultranationalist Ketsumeidan, or "League of Blood," during the political turbulence of the early Showa period. During the Second World War, the metals collection ordinance stripped the interior of much of its bronze and copper fittings. After the war, parts of the fourth and fifth floors were requisitioned by the General Headquarters of the Allied Occupation until 1947. Through all of this, the granite shell remained, scarred but standing.

Why It Was Designated an Important Cultural Property

When the building was designated a National Important Cultural Property on December 25, 1998, the Cultural Properties Protection Council cited two principal grounds. Aesthetically, the great Corinthian colonnade rising the full height of the exterior, together with the interiors of the bank and trust company business halls on the first floor, were judged outstanding examples of architectural design and a vivid embodiment of Dan Takuma's three-part design philosophy. Historically, the building was recognized as the oldest surviving American-type office building in Japan and as a representative work of the early Showa period that introduced advanced American construction technology on a previously unseen scale. It was also the first large multi-tenant office building anywhere in Japan to receive this level of protection, opening a new chapter in how the country thinks about preserving its modern architectural heritage.

Highlights for Visitors Today

Although the Mitsui Main Building remains a working office, much of what makes it remarkable can still be enjoyed by the public. The exterior alone repays a slow walk: try circling the block to see how the colonnade reads differently against each of the three streets, and pay particular attention to the relief panels above the columns, each one a small allegory of an industry the Mitsui group once led. The pale Inada granite warms beautifully in late afternoon light.

On the seventh floor, accessible through the airy atrium of the neighboring Nihonbashi Mitsui Tower, the Mitsui Memorial Museum displays the extraordinary art collection assembled by the Mitsui family across more than three centuries. Holdings include six National Treasures—among them the celebrated Shino tea bowl named "Unohanagaki" and Maruyama Okyo's painted screen "Pine Trees in Snow"—as well as more than seventy further Important Cultural Properties spanning tea ceremony utensils, paintings, calligraphy, Noh masks, and Japanese swords. The galleries are designed to evoke the calm of a traditional tea room while sitting inside the western neoclassical shell of the historic building, a juxtaposition that is uniquely rewarding.

The atrium of Nihonbashi Mitsui Tower itself is also worth lingering in. Its 26-meter ceiling incorporates stained glass salvaged from the former Mitsui Number Two Building, set into a contemporary glass volume that frames the historic Mitsui Main Building from the side and creates one of the most dramatic interior public spaces in central Tokyo.

The Surrounding Nihonbashi District

The Mitsui Main Building sits at the heart of one of Tokyo's most historically layered neighborhoods. Directly across Chuo-dori stands the Nihonbashi Mitsukoshi Main Store, whose lavish 1935 building is also a designated Important Cultural Property and traces its origins to the Echigoya kimono shop founded here by Mitsui Takatoshi in 1673. A few minutes' walk to the south is Nihonbashi itself, the stone bridge that has marked the symbolic center of Japan's road network since the Edo period and that is also designated as an Important Cultural Property. The Bank of Japan headquarters, designed by Tatsuno Kingo and completed in 1896, stands just to the northwest and is yet another Important Cultural Property within the same compact area. For visitors interested in the architectural history of modern Japan, few districts in the country offer such a concentration of monumental landmarks within easy walking distance.