As primarily a collector of only one Pokémon I don’t have much to do with a lot of these sets, but my input would be:
- The Unlimited versions of the e-Series sets are all rarer than their 1st edition counterparts I believe, with unlimited e-Series 1 probably being at the top of the list - though not a complete set. See www.elitefourum.com/t/japanese-unlimited-e-series-1-cards-base-expansion-pack/16426/1.
- 5 corrections were made to Japan’s Neo Genesis set at some point after it was launched (it’s unknown when). These aren’t impossible to find but don’t appear anywhere near as often as the regular “error” versions.
- I see a lot more no rarity Base Set cards appear for sale than I do unlimited e-Series 2 through 5 cards - that may be because people have less reason to list those however.
- No rarity Base Set was printed for only 3 months I believe, but it’s worth noting that at the time Pokémon as a video game had been out for 7 months and was featured the front-cover of Japan’s CoroCoro Comic magazine for each of the 3 months it was in print - at the time CoroCoro had an average monthly readership of around 1.7 million, so it is something a lot of people would have at least had some knowledge of (and I’m sure enough product was printed to cater for this) - I like the history of the set but I don’t think it’s as rare as some people make it out to be;
- Cards like those awarded from JR Rallies are just promotions and are hard to compare with the main sets - I imagine there are fewer of those than any of the main set cards though (excluding unlimited e-Series 1 and the Neo Genesis corrections), but that’s just a guess - you could look at train travel statistics to get an idea of how many of those were likely distributed (I’d guess anywhere from 10-50,000);
- There was a thread recently asking about the rarity of No Rarity Base Set, Topsun and Carddass which can be found at www.elitefourum.com/t/rarity-of-topsun-carddass-and-no-rarity-base-set/32059/1
- The original sets were all continuously printed between their launch and at least 2001 - whilst the cards are in no way different, in ~March 2001 Base Set through Neo Discovery were reprinted with different barcodes. I believe this only had a single print-run. These versions are a lot rarer than the regular releases, but I’ll stress that the cards contained inside are no different (the 2001 Neo Genesis packs do not contain corrected Neo Genesis cards, either);
- Decks in general will have a lower distribution, but again it’s hard to compare these to main sets.
I hope that’s of some use.
I know you only want Japanese ‘WotC-era’ cards, but you may be interested in knowing that Japan’s rarest non-promo full-set is probably the unlimited version of World Champions Pack which I believe may have only available to purchase over 2 weekends at 2 separate events in Japan in 2008.