He contributed to the research of modern Buddhist history; he launched the first issue of "Bukkyo Shirin" (Collection of Buddhist history) magazine with Junkyo WASHIO and Koyo SAKAINO in 1894; he published "Dai Nihon Bukkyo shi" (History of Buddhism in Great Japan) in 1897; he compiled and published "Meiji ishin shinbutsu bunri shiryo" (Historical materials on the separation of Shinto and Buddhism during the Meiji Restoration) with others including Zennosuke TSUJI in 1926.
この間、1894年、鷲尾順敬・境野黄洋らと雑誌『仏教史林』を創刊し、1897年、『大日本仏教史』を刊行、1926年、辻善之助らと『明治維新神仏分離史料』を編纂・刊行するなど、近代的な仏教史研究に大きく道を開いた。