Former Mitsui & Co. Taipei Branch

The Former Mitsui & Co. Taipei Branch (三井物產株式會社舊廈) is a designated municipal historic site located at No. 54 Guanqian Road in Taipei's Zhongzheng District. The building stands as one of the most significant surviving structures from the Japanese colonial era's commercial district, embodying the immense economic power that Japan's zaibatsu conglomerates wielded over colonial Taiwan.

Mitsui & Co. (三井物産株式会社), founded in 1876 by Takenosuke and Yonosuke Mitsui, was the trading arm of the Mitsui zaibatsu — Japan's oldest and largest industrial conglomerate. In colonial Taiwan, Mitsui became the dominant trading company, trading in commodities such as tea, rice, and sugar and acting as sales agent for government monopoly products such as camphor. The company's investments extended across banking, insurance, mining, forestry, and manufacturing, covering nearly every sector of the colonial economy. Mitsui's operations were initially based in Dadaocheng (大稻埕) along the Tamsui River, Taiwan's primary commercial hub during the early colonial period.

As Taipei's economic center shifted southward to the newly developed Honmachi (本町) commercial district near the Taiwan Governor-General's Office, Mitsui relocated its headquarters to the prestigious intersection at what is now Guanqian Road. The new building, credited to Hirano Yūzō (平野勇造) and Nomura Ichirō (野村一郎), was begun in 1920 and completed in 1922. The original structure was a three-story Western-style building in the Renaissance Revival style (辰野式), featuring a distinctive corner tower with a pointed spire, ornamental columns, and sophisticated architectural detailing befitting the prestige of Japan's most powerful trading house.

How the building acquired its present appearance is disputed: one account holds that it was rebuilt in 1940 because of structural decay, while other research indicates that it was severely damaged by Allied bombing during World War II and that architect Lu Shu-sen (盧樹森) rebuilt it between 1946 and 1947. The rebuilt structure retained its three-story scale but adopted a simplified modernist aesthetic with horizontal window bands and restrained decorative elements, reflecting the post-war austerity. The interior features unusually high ceilings, with floor heights equivalent to a typical five-story building, and the grand hall retained its pre-war elevator — a rare luxury in 1920s Taipei.

In the post-war decades, the building served a succession of government functions. Until 1988 it housed the headquarters of the Veterans Affairs Council (國軍退除役官兵輔導委員會); Chiang Hsiao-wu was among those who worked there in the early 1970s. It subsequently became the Taiwan Land Bank Taipei Branch office, and from 2000 to 2009 housed the Supreme Prosecutors' Office Black Gold Investigation Center and later the Special Investigation Division. The building was designated a Taipei City Municipal Historic Site on July 22, 1998; after the Administrative Court annulled the designation in May 2000 on the owner's appeal, the city government designated it again and the bank dropped further litigation. It is currently owned by the Taiwan Land Bank and remains closed to the public, though its exterior — facing the entrance of 228 Memorial Peace Park — continues to anchor one of Taipei's most historically significant streetscapes.