A reference to the "Provisional Rules of Unified Progressive Taxation in the Shanxi-Henan-Shandong-Henan Border Area", promulgated on April 25, 1943. The unified progressive taxation was a system of taxation introduced by the anti-Japanese democratic government during the anti-Japanese war. Under this system, several taxes simultaneously levied on assets and income in rural areas were combined into one. An increase in minimum taxable assets and income was accompanied by an increase in the tax rate.