The Four-Corner Method was extremely popular in government education circles to promote spoken language unification until pronunciation-based systems became fashionable in the mid-1930s.
The first large-scale project to promote spoken language unification was in 1936: [[Wang Li (linguist)|Wang Li]]'s 4-volume Mandarin Phonetic System (MPS) entry, Guoyu Cidian (Kuo-yu Tz'u-tien). In 1949 it was re-edited into the MPS [[Hanyu Da Cidian]] with [[Kangxi Emperor|Kang Xi]] 214 radical index, and a small Four Corner dictionary was available as the Xin Sijiaohaoma Cidian of 1953. After 1949, limited use of MPS and the original Four-Corner Method continued under the People's Government, until the introduction of [[pinyin]] in 1958 and after. Today's Chinese dictionaries still contain MPS characters below each Pinyin class entry and sometimes in a phonetics chart in tables (Xinhua Cidian), while main entries are all in Hanyu Pinyin order. There is one all-sijiaohaoma small dictionary (Third Revision, below).
