You can search statistical data on every fields by prefecture, which you have to  group together from huge collection of books and microfilms without this database.
For example, you can easily get the data like following:

- Transition of rice production by prefecture in Meiji period
- Number of teachers of a certain prefecture by sex and age in prewar period

[Contents]
0.9 million images, 1.5 million records of Prefectural Documents on Statistics (1873-1972)
 

The chief objective of the Taiwan Colonial Statistics Database lies in the preservation of official statistical records from the Japanese colonial period. It contains digitized materials mainly from the National Taiwan University and National Taiwan Library collections, including 684 volumes of Japanese colonial statistical records, 194,075 digital images, and 103,732 sets of metadata.
There are 29 data categories in total, including law and law-related areas.

You can search statistics announced by each ministry or Cabinet Office or Bank of Japan.

OECD iLibrary is the online library of the Organisation for Economic Cooperation and Development (OECD) featuring its books,  papers and statistics and is the gateway to OECD’s analysis and data.

You can cross-search the largest knowledge database in Japan that accumulates the encyclopedias, the dictionaries, news, and scientific site URL collection, etc.

It was renewed in "JapanKnowledge Lib" in April, 2014 and also "National History Dictionary" and "Encylopedia of Japanese Historical Place Names” were integrated.

From March 2017, "Jinbutsusosho" is available.