One of the most confusing Korean issues for collectors to identify is the 1955-58 series that show the industrial reconstruction of South Korea after the Korean War. The reason that there is confusion about these issues is that there were four different types of paper and two slightly different images used in producing the series, using the same colors for the different denominations during the period of 1955-58.
On the surface, all of these stamps look very similar to the collector. However, there is a big difference in value for one of these stamps because of the type of paper that was used for printing it, and it is valued at $1500. Another stamp of the same denomination, which was issued only 8 months later, with the same image and colour, has the catalogue value of only $5.00. As you will see, it is very easy to get these issues mixed up.