Postage due cover from Hankow to England. ICP 5c x 2 canceled by Hankow Dollar Dater on Feb. 18, 1899. Hong Kong 2c vertical pair canceled by Hong Kong P.O. CDS on Feb. 24, 1899. Hong Kong P.O. Circular T mark. "3D" marking for postage due.
The international letter rate at that time required 10c Hong Kong stamp, about UK 5d (indicated by the handwritten "5d"), therefore, the cover was 6c or 3d underpaid.