These portal sites provide a variety of information on historical topics and periods, largely web-based resources rather than print or digital archives.
A group of website "guides" ガイド provide information tidbits on various periods of history in blog style, drawn from their reference materials largely focused on historical figures. They also have active and entertaining Twitter accounts.
These databases, webpages, and guides are useful reference sources for the study of history of all periods in Japan.
These are databases that cover a variety of subjects and time periods that facilitate the study of Japanese history. They include finding aids and catalogs, as well as digitized images and documents.
These digital archives are relevant to the study of the pre- and early modern history of Japan.
These digital archives cover a variety of topics and are relevant for Japanese history from the Meiji to contemporary periods. They include images as well as documents.
Shashi Interest Group and Shashi
The Shashi Interest Group was founded to facilitate information sharing about company histories in Japan among researchers, librarians, and other interested parties. Their email archives and wiki can be viewed online; you can also sign up for their mailing list and read their open access journal, Shashi.
Shibusawa Shashi Database 渋沢社史データベース
This database allows you to search over 1000 company histories, as well as browse.
Jitsugyōshi Kenkyū Jōhō Center 実業史研究情報センター
The Jitsugyōshi Kenkyū Jōhō Center runs a portal for research into company histories, including historical information on companies, directories, indices, databases, and information related to Shibusawa Eiichi. This is a center run by the Shibusawa Eiichi Memorial Group.
Digital-ban Shibusawa Eiichi Denki Shiryō デジタル版『渋沢栄一伝記資料』
This digital version of Shibusawa Eiichi denki shiryō provides either full text or page images of all 68 volumes of the series. The database is keyword searchable (from free-text keywords and the index of volume 1) as well as browsable by volume and author.