Yamakawa Shuppansha is the publishing enterprise in Japan known for their history and geography textbooks.
According to PR-model, yamakawa.co.jp is ranked 344,538th in multilingual Wikipedia, in particular this website is ranked 25,333rd in Japanese Wikipedia.
The website is placed before accc.gv.at and after freekeene.com in the BestRef global ranking of the most important sources of Wikipedia.