Figure 4 is kind of a repeat, but it does show the older large size of the box and the “14″ as part of the chop and not a write-in. At the bottom, it says “Kwang Ju P.O.”
Figure 5 is of interest in that the bottom box where the post office name is to be given doesn’t use the word for post office but just says “Kwang Wha Mun,” suggesting that, if you don’t know that Kwang Wha Mun is, the second most illustrious p. o. in Seoul, then you’re really not with it.
(Kwang Wha Mun is/was essentially at the very heart of Seoul. It is also essentially at the corner where Seoul’s main north south street and east west street intersect. It would also be good to remember that many of Japan’s postal cancellations were done right at Kwang Wha Mun.)