Before 1976 local governments in Korea were allowed to print their own revenue stamps for use within their own city (시) or county (군). This meant that until that year hundreds of different revenue stamps must have been in use in Korea. Often these local governments even printed several series of revenue stamps, sometimes even starting pre-1962 with hwan value series. This example is from 연천군 (Yeoncheon County) through which the border with North Korea runs.
This type of document is a 호적등본, a certified copy of a family register, issued in 1975. Since revenue stamps are usually found on the back of official documents (as per the rule, to avoid important text disappearing beneath the stamps) this is the front of the certified copy:
The stamps totaling 80 won can be found on the back. Notice that the stamps come from the top left corner of the sheet in which these stamps were printed. Also, the stamps were not perforated but rouletted.
(Names have for privacy reasons been digitally deleted.)