Brunei Japanese Occupation Rare 8 Cents Stamp

This is my latest acquisition - a very rare 8 cent stamps overprinted by the Japanese Imperial Government for use in Brunei during the Second World War. The 8 cents stamp even without overprints are rare as not many were produced. This one cost me US$230 which makes it the most expensive among my 15 Brunei overprint Japan stamps. I thought I had completed my series but there are sill 5 stamps which I still need to collect.

The catalogue value for this stamp is US$760, so the US$230 I paid for is worth it. The other expensive values will be the $5, $25 and $3 overprints. I am trying to get the 16th stamp which is the 30 cents overprint. Luckily that only has a CV value of US$105 but I probably have to pay much higher than that.