English Language

Kodansha Encyclopedia of Japan. 9v.
Perkins Ref: DS805 .K633 1983
The articles are by eminent scholars and advanced graduate students; longer articles include a bibliography. Excellent for a summary of the scholarship and as a place to begin. Somewhat dated unfortunately, but has not been superseded.

• Japan: An Illustrated Encyclopedia. 2 v.
  EA/ Perkins/ Lilly Ref: DS805. J263 1993
  A revised and abridged version of the Kodansha Encyclopedia of Japan. Available in both print version and online through  JapanKnowedge http://library.duke.edu/metasearch/db/resource/Japan+Knowledge.

Encyclopedia of contemporary Japanese culture
Perkins Ref: DS822.5 .E516 2002
Covers literature, film, architecture, food, health, politics, economics, religion and technology, and range from shorter definitions, histories or biographies to longer essays treating major issues and ideas in depth.  Entries are signed. A-Z format.  Includes cross references and suggestions for further reading.

Japanese Language

Britannica international encyclopaedia
ブリタニカ国際大百科事典 29v.
EA Ref: AE35.2 .B875 1988

Sekai daihyakka jiten.
世界大百科事典 26v.
EA Ref: : AE35.2 .S4 1988
Earlier editions of Heibonsha encyclopedias are in the stacks under the title Dai hyakka jiten.

The articles in these Japanese encyclopedias are signed but do not have bibliographies.  All entries are arranged in gojuon order, but many entries require use of the index.  Particularly useful for comparisons of Japanese and world phenomena. No biographical entries for living people, although they may be mentioned under other topics.  Well-indexed. 

Koji ruien
古事類苑　 51v.
EAC: AE10.J3 K62 1981
Last of the traditional Chinese-style encyclopedias. Collection of primary source materials selected from books published before 1868. Intended to preserve traditional Japanese culture, covers all phases of life in premodern Japan. Classified by subject into thirty sections.

Nihon dai hyakka zensho/ Nipponica
日本大百科全書 / ニッポニカ
A 30 volume Japanese language dictionary available online through  JapanKnowledge .