Historical Encyclopedias 

Kokushi daijiten  国史大辞典 (JK)

General - Nihon dai hyakka zensho  日本大百科全書 (ニッポニカ) (JK)

Place name

Nihon rekishi chimei taikei  日本歴史地名大系 (JK)

Language Dictionary

            For Kanji - Jitsū  字通 (also available on JK)

            For Kana  - Nihon kokugo daijiten  日本国語大辞典 (also available on JK)

English dictionary for historical terms

On-line Glossary of Japanese Historical Terms  応答型翻訳支援システム 

(Historiographical institute of Japan, The University of Tokyo)

Personal Names, Biographies, Genealogies

Reading and Writing Japanese Names and Who’s Who

            Nihon jinmei daijiten  日本人名大辞典 (also available on JK)

            Library OPACs in overseas

Full text  Tōyo bunko  東洋文庫 (JK), Hathi Trust

Journal index

Zasshi kiji sakuin (NDL), Magazine Plus, Kōseisha zasshi kiji sakuin, CiNii, JAIRO, BAS (English), EAL Online English journals

Book or historical material search

Kokushi Somokuroku  国書総目録 (and other databases from NIJL), WebCat, Kinokuniya Book Web, etc