This is the 16th stamp of the 20 stamp set of Brunei Japanese Occupation. The others which I am looking for is the 6c red stamp, the $5, the $25 and $3 overprints which all have catalog values of four to give digits.
This 30c stamp cost me US$135. Its catalog value is much lower at around US$100 but the opening bidding price was already at US$125. So the catalog value should be revalued higher. I had a tough time searching for this stamp and the moment I saw it I thought I will grab it.
It's an ordinary 30c 1924 issue but I think by the time of the Japanese occupation, there was not much of this issue left for them to overprint. Hence the scarcity of it. Similarly with the 8c grey which has a catalog value of around $2,000+. I purchased that the other day for around M$700+.