Issued on April 28, 1929 to commemorate National Unification, this mint never hinged block of ten features the 4 cent gravure-printed Chiang Kai-shek stamp in olive with Yunnan provincial overprint. Line perforated 14 and honoring the leading political figure of the era, this regional issue celebrated the consolidation of central authority under the Kuomintang after the Northern Expedition. Catalogued as Scott YU22, Michel CN-IM-YU 22, Yvert et Tellier CN-YU 22, Stanley Gibbons CN-IM-YU 22, and China Stamp Society CN-IM YN23, the block is an important artifact of China's post-warlord unification era. All stamps are very fine mint never hinged examples with full original gum and strong typographic clarity. Estimate "$180 – 220"