in 1894 japan invaded the qing dynasty in manchuria and taiwan and as well as korea . in 1899-1901 the boxer rebellion happened and japan invaded china again but allied with russia, germany, austria, france, britain and america to support yuan shikai to stop empress dowager cixi. this led to the fall of the qing dynasty in the 1911 xinhai revolution, the country was thrown into turmoil. in the ensuing power vacuum, a large number of warlords seized control of different parts of the country. to defeat them and unify the country, sun yat-sen and his kmt sought help from foreign governments.