When the new KSS website was launched, I wrote an article about a number of Korean stamps I had been searching fo, that I was never able to find. There is an article titled “Do these Korean stamps actually exist?” that was published on November 30, 2018.
In the article I noted: I have been collecting Korean stamps for nearly 60 years and there are some Korean stamps I have never seen mint or used, even with low catalogue values, and I wonder if they exist? These are Scott numbers: the 1900-01 series, 20Ba, perforation 10 2ch pale, cat. value $50 mint, $45 used; the 1946 issue 58b Double Surcharge, 20ch on 6s ultra, cat. value $30 mint, not listed used; 1951 issues, 129a inverted surcharge, 300wn 10wn, cat. value $32.50 mint, not listed used; 130a inverted surcharge, 300wn on 20wn, cat. value $35 mint; 1952 issue 174a inverted surcharge, 300wn on 4wn, cat. value 32.50 and 181a, inverted surcharge, 300wn on 100wn, cat. value $45 mint; 1956 212E, 15h violet, horizontal laid paper, Scott mentions, no cat. value.