Tips to search legal materilas: by Robert Britt, Coordinator of East Asian Library Services, University of Washington, Marian Gould Gallagher Law Library
Japanese Legal Research Guide, Web Resources A-Z, “Legal History” section:
You can look up the history of changes to particular laws in NDL’s Abolished Laws Database [日本法令索引廃止法令検索]: http://hourei.ndl.go.jp/
Laws change over time, and it’s important to know which specific year you want to see. The law may have changed many times between 1910 and 1945, for example. Finding “snapshots” of a law for a given point in time can be done using print publications such as various versions of “roppo” (六法) . Roppo Zensho at Law Library (2014 - ).
University of Michigan, there are a number of these annual publications going back many years. Also, each law and it’s various amendments over the years are also separately published in both法令全書and官報.
Historical Kanpō for the years 1883-1952 is available in NDL’s “Online Digital Library”, with advanced searching (“詳細検索”):