Imagine a cup like this: A pure silver sake cup, decorated with a hand-carved image of the aircraft carrier Akagi with planes taking off and its distinctive funnels visible. The back of the cup has the words "Congratulations on Victory" "December 8th, Showa 16th Year" and the name of the person receiving the cup "Admiral Nagumo Chuichi". Even better, it comes with an original wooden box, and on the inside of the lid has a beautiful hand written message, maybe something quoting Admiral Togo, and signed by, say, Hideki Tojo (because Yamamoto probably wouldn't have called it a victory so fast). Now, this cup probably doesn't exist - even if it does, we're never likely to see it on the market. However, as rare cups go, it would shoot straight to the top.
This hypothetical cup is rare for a reason - it's made of a rare material among cups (pure silver). It's decorated with a rare and, in this case, valuable theme (aircraft carrier Akagi). And it's also got a rare and important provenance. All combined, it makes for a very rare and also expensive cup. As the title of this post suggests - rarity is a three part combo. It consists of materials, decorations, and provenance. This is probably true for collectibles. Of course, in some cases provenance and historical significance outweigh the other factors - most militaria is like that. That ID plate for the Zero fighter that was downed in Pearl Harbor that recently sold on eBay is worth a lot because it's a Zero downed in Pearl Harbor. If it's just any other Zero ID plate it's not nearly as interesting. For these commemorative items, however, the artistry, thematic interest, and beauty come into play as well.
I'm going to spend the next three posts talking about each of these three aspects in more detail. In the meantime, just consider this item:
It basically has all three of these factors - although of course not quite at the level of that hypothetical cup I talked about at the beginning of the post. It's a rare image, it's lacquer in a complete set, which is generally rarer (and have cups that are better made) than the porcelain ones, and it's also got a nice provenance. The back of the cup says "Great East Asian War Participation" "Moritama-unit". Moritama unit referred to the 4th Air Group, which was formed in 1942 and flew out of Rabaul supporting the other units there. It's a gem.