Mitsui Bunko to Release About 15,000 Digital Images of Mitsui Business Historical Materials Online from May 18

The Mitsui Group and the Mitsui Bunko Public Interest Incorporated Foundation have been working since 2023 on the “Digital Archive Project for Historical Materials Held by Mitsui Bunko,” commemorating the 350th anniversary of the Mitsui Group. The project is creating digital images of about 30,000 items from Mitsui Bunko’s holdings, including early modern materials such as Mitsui family records and modern corporate materials from Mitsui Bank, the former Mitsui & Co. (Note 1), and Mitsui Mining. Preparations have now been completed to release about 15,000 images related to Mitsui’s business history, and online publication will begin on Monday, May 18. The materials to be released cover Mitsui’s business activities in the early modern period, namely the Edo period, and the modern period from the Meiji era through the dissolution of the zaibatsu. They are valuable resources for understanding Japanese business history, economic history, and modern and contemporary history. The archive includes large-scale releases of images such as the Omotokata Kanjo Mokuroku, Mitsui’s early modern consolidated settlement ledgers that show business trends over roughly 160 years from 1710, and the Osaka Ryogaedana Nikkiroku, business diaries of the Osaka money exchange shop that record daily operations as well as weather, daily rice prices, and exchange rates. This is Mitsui Bunko’s first initiative to publish digital images of its holdings online, and it represents an unprecedented scale of release. Through this online publication, Mitsui’s historical materials can now be shared worldwide. The archive is expected to be used by a wide range of people, including researchers in Japan and abroad studying Japanese business history, economic history, and modern and contemporary history; teachers from elementary through high school; students interested in Japanese and economic history; general users researching family history; and those involved in compiling corporate histories and local government histories. The project aims to communicate Mitsui’s history broadly around the world. Note 1: Legally, the former Mitsui & Co. and the current Mitsui & Co. have no continuity and are entirely separate corporate entities. Project overview: The project is a five-year plan from fiscal 2023 through fiscal 2027, with fiscal 2026 being the fourth year. As part of the Mitsui Group’s 350th anniversary commemorative projects, approximately 30,000 items are being digitized from about 82,700 business archive materials within Mitsui Bunko’s roughly 100,000 holdings. About 15,000 of those items will be released this time, with about 20,000 items scheduled to be made public by the end of the project period. Publication date: Monday, May 18, 2026. Access will be free of charge. Users must register and receive an ID and password, and the usage period is unlimited. Applications will be accepted on the Mitsui Bunko Archives website from May 18. If material images are to be published in media or similar outlets, a separate application and publication fee are generally required. Materials to be released: The project targets business materials from the early modern period, or Edo period, and the modern period from the Meiji era through the dissolution of the zaibatsu. It will publish digital images of materials that are highly valuable for research or frequently used. The scope includes ledgers, reports, proposals, regulations, letters, drawings, business guides, and other documents related to business activities. Examples include: 1. Kakae Yashiki Ezu: drawings of town residences owned by Mitsui in Edo. These materials are also used in architectural history research and help visualize the structure of Edo town residences, making them valuable for urban space studies. 2. Ieari-cho: a list of all land owned by Mitsui in Edo, Kyoto, Osaka, and Matsusaka during the Edo period. It records locations, size, prices, and acquisition dates, and is one of the basic sources for studying Mitsui’s landholdings in the Edo period. 3. Former Mitsui & Co. “Diaries”: business diaries of the former Mitsui & Co. head office, providing valuable information on transactions, employee movements, personnel matters, and communications with Mitsui Bank, the government, and public agencies. 4. Mitsui Gomei Kaisha “Board Meeting Records”: records of board meetings at Mitsui Gomei Kaisha, which oversaw all Mitsui businesses. The board reviewed and discussed important matters not only for the partnership itself but also for the former Mitsui & Co., Mitsui Mining, and other entities. These records provide an overall view of key decision-making by the Mitsui zaibatsu from 1924 to 1940. Mitsui Bunko is a nonprofit research institution consisting of the Mitsui Bunko Archives, which preserves, publishes, and conducts research on social and economic history materials, and the Mitsui Memorial Museum, which preserves, publishes, and researches works of art.