It was taught in primary schools to children in Shanghai and other locations during the late 1920s and throughout the 1930s, up to the outbreak of war with Japan in 1937. 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's 4-volume Mandarin Phonetic System entry, Guoyu Cidian. In 1949 it was re-edited into the MPS Hanyu Da Cidian with Kangxi 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 in the People's Republic of China, 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). Second Revision A minor Second Revision was made during and just after World War II. This was used by most postwar lexicographers including Morohashi Tetsuji, who created his 12-volume Sino-Japanese dictionary, the Dai Kan-Wa jiten and included the Four-Corner index among several other lookup methods. Oshanin included a Four Corner index in his Chinese-Russian dictionary and an edition of the 25 Histories (Ershiwu shi) was published in the early 1950s with a Four-Corner index volume containing the entire content. Then, in 1958, with the introduction of pinyin, a small Xin Sijiaohaoma Cidian was produced by the Beijing Commercial Press, but the rapid Han character simplification of the following years made the small (30,000 compound) book obsolete in China. Overseas and in Hong Kong, it remained popular for a number of years as a high speed key to phonetic dictionaries and indexes. It was used by those partly literate in or unfamiliar with Standard Chinese, especially Hanyu Pinyin. Wang Yunwu produced a Xiao Cidian and Zonghe Cidian in the late 1940s; the latter remains in print in Taiwan, with an auxiliary section of rare characters and gives the telecode number, radical and stroke counts for each character. Third Revision During the Cultural Revolution in mainland China, the Four-Corner Method underwent a radical Third Revision during the compilation of the experimental volume of the Xiandai Hanyu Cidian, Commercial Press, Beijing,