A few years ago, my French Polynesia stamp club tried to corner the market after spending years being defensive. For the first time, the club launched an offensive attack by monopolized a specific target. That specific target was French Polynesia's 1969 Napoleon stamp sheet. These sheets were vulnerable because only a few dozens survived. Some were discard & some were accidentally ruined by collectors. To make things worse, a fire broke out at a stamp shop that destroyed several sheets. The sheet couldn't be seen in the public, private or even in the black market.
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After 32 years of disappearance, two sheets suddenly appeared at a private auction in Paris - the only two sheets exist on Earth. In auction, our stamp club outbid everyone & won both sheets. Some of our members were upset because they weren't consulted. Some were disgusted because there were no election or meeting. I was dismay because I dislike monopoly. In 2017,a Frenchman came forward with a sheet - the third sheet in the world. I was happy & hopefully there are more sheets somewhere out there.
Napoleon stamp in MNH ($55 - $95)
French Polynesia Stamp Club