In 1967, Seoul police broke up a large counterfeiting ring that included post office officials. The group had forged 20-won, 40w, 50w and 100w definitives, sold by clerks who received a commission on their sales. Forgeries amounted to about 10 percent of sales for several months at some post offices. As with most postal forgeries, these counterfeits are now far more valuable than the actual stamps.
Korea 1963 20-won Meesun Blossoms, Regular Issue – Scott 369
Forgery: The second character from the top in the top-right corner of the stamp consists of an inverted “V” and an upright with a line extending from its midpoint. That line does not touch the inverted “V.” There is a dot of color on the upper edge of the first leaf under the line of characters in the top-right corner. The upper line of the topmost leaf that extends to the right from that same branch is solid. The paper fluoresces brilliantly under ultraviolet light.
Genuine: The line extending from the upright of the second character in the top-right corner touches the inverted “V.” There is no dot of color on the edge of the first leaf extending to the right under the line of characters. The margin of the uppermost leaf extending to the right from the right-hand branch usually shows a distinct break near its tip. The paper does not fluoresce.
Reprinted by permission from the July 24, 1995, Linn’s Stamp News. Sidney, OH.
(Originally from KP February 2007, Vol. 52, No. 1)
Interestingly several articles were published in the Korean Philately in August 1967 about this exact situation! Here is an example page from that KP, showing headlines in English language newspapers about these forgeries:
Here is another example from the August 1967 KP, giving pointers on how to identify the forgeries: