Stamp Giveaway # 6 (Odds and ends) [solved]

This lot runs from cheap to very expensive, from complete sets to partial sets and mostly older sets and an unidentified used stamp. I obtained the Timor and Riau stamps as part of my ASEAN collection. Otherwise I have no idea how I ended up with the other stamps.

Mauritania, Michel West Africa 2013 catalogue 122-126, unused lightly hinged, 4.60 Euros
very small stamp, used, perhaps connected to Cervantes anniversary in 1947 but I could not find it in catalogues now
South Korea, Michel Japan Korea Mongolia former Soviet Union in Asia 2014 catalogue 25-26, unused never hinged, 35 Euros
Ukraine, Michel East Europe 2014/15 catalogue 1B, unused never hinged, 30 Euro cents
Timor, Michel Southeast Asia catalog 2015 257, NY World's Fair, unused lightly hinged, 400 Euros
Riau, Michel Southeast Asia catalog 2015 24, unused never hinged, 22 Euros

The questions: What year was the Ukrainian stamp issued and what was the full official name (in English) of the government that issued it?
Why is the Timor stamp so expensive?

First correct response received by July 11, 2021 noon eastern US time will be declared the winner. If there are no correct responses, the first response received will be declared the winner. All responses in English please. My decision of winner will be final. I invite all those interested to enter and watch for future giveaways.

Will

The Ukrainian stamp was issued in 1918 by the Ukrainian People's Republic (UPR), or Ukrainian National Republic (UNR).
Wild guess for the second answer: because of the deviating colour? It should be red-brown in stead of red?

That and the stamp for the international exposition in New York?

Essor Prof, Sorry, my scanner seems to be emphasizing the red but the Timor stamp is more red-brown in reality. And that is not the answer in any case.

Ashlobo, Can you clarify your statement about the international exposition in New York? Do you mean it is expensive just because of its subject matter?

Some Portuguese Macau stamps were overprinted with "Timor" until 1898.

The Timor stamp in question here was most probably the earliest and independent non-Macau stamp issued after 1933.
This stamp was mainly used as a wartime postal stamp in WW2 wlhen the prisoners of war locked up in Japanese cells wanted to send a letter to their home....
I guess that made it more expensive in NY

From 1938 to 1946, no colonial stamps were issued by the Portuguese authorities. Only the Japanese did.


From Dili to NY in WW2.

Quote: "Coinman48"​Essor Prof, Sorry, my scanner seems to be emphasizing the red but the Timor stamp is more red-brown in reality. And that is not the answer in any case.
​
​Ashlobo, Can you clarify your statement about the international exposition in New York? Do you mean it is expensive just because of its subject matter?

​well I was caught by the year 1939-1940 which was during the outbreak of war in Europe. The US did not participate till the year after while Portugal was officially neutral. I don’t know much about stamps, but the stamp of the Exposition would suggest that there are no so many available of these. I believe the Japanese did not occupy Timor until 1942, however they were probably in de facto control much before then.
The interesting thing about Portuguese colonial mail was that the dominant colonial power in the region would typically actually carry the post… so the British in India, and I suppose the Dutch or British for Timor

Id be interested to hear in the end what the exact reason is!

Interesting responses but in the case of Timor not what I am looking for.

Will

Quote: "Coinman48"​Essor Prof, Sorry, my scanner seems to be emphasizing the red but the Timor stamp is more red-brown in reality.

​That's why I said it was a wild guess. I know scanners never give the exact colors. But of course now I'm very curious too about the real reason.

That authentic overprint "New York International Exhibition 1939-1940" makes that stamp so expensive?

Quote: "Coinman48"​Essor Prof, Sorry, my scanner seems to be emphasizing the red but the Timor stamp is more red-brown in reality. And that is not the answer in any case.
​
​Ashlobo, Can you clarify your statement about the international exposition in New York? Do you mean it is expensive just because of its subject matter?

​Another wild guess - was this like a semipostal stamp, limited overprints.
The overprint was done to raise money for a charitable cause perhaps? Was it sold only to patrons who made a major donation.

Still waiting for the reason as I understand it.

Will

The Ukrainian stamp was issued in 1918 by the Ukrainian People's Republic (UPR), or Ukrainian National Republic (UNR). (Thanks Essor Prof)

Another wild guess...The Timor stamp is so expensive becausetThe World's Fair symbol (Trylon and Perisphere) is incomplete and reversed. Should look like this:

Since we're all guessing, another wild guess (although it's pretty much the same as my previous one): Timor had a temporarily post office at that International Exhibition 1939-1940 in New York?

Just noticed that the 50 and A. are off Centre in your stamp vs the specimen. Maybe that’s not a big deal because it seems that those are overprints

Because this stamp was only used in New York

Frenchlover is as close as anyone can get. So he is the winner! The stamp, along with similar ones from other Portuguese colonies, was sold only in New York at the exhibition. I assume sales were not at temporary post offices for each colony but at the Portuguese pavilion.

Congratulations, Frenchlover! I will send you a PM asking for your address so I can send your stamps right off. Thanks to all who participated!

Will

I do like stamps !