American Postal Machine Company, U.S. Postal Agency Shanghai, Mar 31, 1906. Flag cancel (type Q14(1)) on Chinese Imperial Post postal card to San Francisco, franked with 1903, 1¢ blue green (corner tear at upper right), some letters light or not visible and partially overstruck by Seattle machine cancel, F.-V.F., known use of about one week in late March and early April of 1906. One of the most sought after of all flag cancels. Scott No. 300  Estimate $5,000 - 7,500. $0 (Image)