Business Information: Matthew Bender publishes a guide to Doing Business in Japan that is available through Lexis (MATBEN;DBJAPN). Deloitte posts a Tax and Investment guide for Japan. See also the sources listed in "Doing Business in Foreign Countries."
Company Information: Teikoku provides financials and basic information for a large number of public and private Japanese businesses. Teikoku company reports are available from Lexis (COMPNY;JPCORP), Skyminder, and directly from Teikoku.
If a Japanese company trades in the U.S. as American Depositary Receipts (ADRs), you can get Form 20-F filings from EDGAR.
EDINET, the Japanese equivalent to EDGAR, provides public company filings in Japanese. EOL is subscription based service that provides high-level current and historical information for all public and some private companies. The Japan Company Handbook provides 1-page snapshots for all public companies; the Handbook is available on Lexis (COMPNY;JCH). The International Institutional Database, also on Lexis (COMPNY;MGINTL) has financials and stock prices for many Japanese companies.
Alacra sells information about Japanese businesses from a number of different sources, including Thomson Ownership (to identify shareholders).
For more sources, see the separate "Company Information" entry.
Intellectual Property: The EPO's Japan page provides information about Japanese patents and tips on searching even if you do not know the language. See also Patents - Foreign, Trademarks and/or Copyrights.
Legal Materials: For an introduction to the Japanese legal system and for links to Japanese legal materials see the Guide To Law Online: Japan by the Library of Congress and/or The Japanese Law Research Guide. To learn about more Japanese legal materials available in English, see the "Foreign Laws" entry of this Guide.
News: Free, current news is available from News on Japan, The Japan Times Online and Japan Today. Westlaw has fee-based databases for Japan News (JAPANNEWS) and Japan Corporate News (JPNCNWS).
Translation: The New York-based Translation Company (800-322-8269) provides translations, as does the Japan Society in New York City.