This block of four mint never hinged stamps features the scarce red $2 Gold Yuan surcharge on a blue $50 fiscal issue, originally printed for tax purposes and later authorized for postal use during the Republic of China's economic collapse in early 1949. Printed by Dah Tung using lithography, this emergency issue displays detailed transport imagery including a steam locomotive, passenger ship, and aircraft, symbolizing national infrastructure amidst hyperinflation. The red overprint includes a small "2" with a distinctive "Y" in the lower right, identifying it as a localized Gold Yuan conversion marking. Printed on unwatermarked, ungummed paper with variable perforations, each stamp measures 25 x 22 mm. The block belongs to a broader series of revenue stamps revalued for postal service, a testament to the severe fiscal instability and decentralization of printing during the final months of Nationalist governance. Catalogued as Michel CN-IM 986I, Scott CN-IM 915a, Yvert et Tellier CN-IM 749, Stanley Gibbons CN-IM 1127, and China Stamp Society CN-IM 1309. Condition Mint never hinged block with strong red overprints, clean margins, and bright color. Estimate "$80 – 100".