Figure 6 shows what could happen as a result of a local p.o. making its own chits for postage due notification. It is a simple slip of paper that gives the number “58” at the top, “receipt” in the middle, and “amount 20 (written in) won” at the bottom. The envelope really has two notifications of postage due as the 2-inch long rectangular chop in purple also notifies of postage due. Now the question arises, did the sender actually think a TB seal would get the letter sent? TB seals and stamps were essentially the same price at that time.
Figure 7 is a good example of unnecessarily saying “you owe postage” twice. There is the older type chop with a 10 won write-in and the newer postage due slip also with the 10 won write-in. There seems to be the idea that “we have the chop and now we have the slip, so we might as well use them both.” The chits usually measure about 50 mm in length, and on the bottom line there is plenty of room to chop in the name of the post office, except that most slips have left that space unused except for the Inchon P.O. which has faithfully chopped in “Inchon” in Figures 8 and 9.