Back when Yokai released, Score Entertainment did something entirely new with the Inuyasha TCG. They began to include specially signed Rumiko Creation cards in booster packs. There were 2 total in each set, both sporting a "1 of 1" stamp on them and Rumiko Takahashi's signature on the right. As you can imagine, the odds of you pulling one of these were insanely low considering there were 2 cards and both were different from each other. This ran through to Keshin, with no RC cards being included in Tensei and the remaining 4 RCs being handed out at West and East Coast Championships in 2007.
While this was all happening though, Score Entertainment made an error. They included the RC cards on their uncut sheets that would be sliced up and placed into booster packs. As luck would have it, some unsigned RC cards would end up in packs. Strangely enough, however, these cards were basically completely black and difficult to see the card text, pictures, etc etc. These were actually test prints that Score Entertainment ran for every set. To my knowledge, only 5 black version RCs have been found, with multiples of some being found. The 5 found are RC2, RC4, RC7, RC8, and RC11. If you own one of the others not listed as a black version, please contact me! RC7 and RC8 have been pulled 3-4 times out of Saisei packs, as an FYI! Now, aside from all of this, there is a set of 19 RCs that exist without signatures but are the light version. RC3 was missing from that set, I believe. These were extremely likely to be the "Score Entertainment vault" set and they were likely taken when Score Entertainment closed their doors. These cards are now in the possession of mirkojaros, a well known collector who is most notable for his DBZ and DBGT collection within the Dragonball Z community.
In Keshin, Score Entertainment decided to make signature cards more accessible and add some specialty to the sets. They released 6 Feudal Voice (FV) cards, 3 Player's Choice (PC) cards, and 2 of the 10 Tensei Preview (I) cards (Miroku and Sango only) for Keshin that would sport signatures on them. The 10 Tensei Preview cards were all available as non-signatures as well. Those were 1 per case, making getting the set of 10, especially the signed copies of Miroku and Sango, extremely difficult. Currently, a few Miroku's and only 2 Sango's have been found. There are 170 of each of the 6 FVs, 20 of the 9 I's, 20 of PC1 and PC2, and 10 of PC3 with signatures on them. One final thing to note is that the Tensei Preview cards do technically exist as black versions, but these have only been found on a single uncut sheet, which was likely a test production sheet. This sheet is currently in the possession of inviso, a well known collector who is most notable for his Yu Yu Hakusho collection within the YYH community.
When we get to Tensei, things get even wackier. Everything was thrown into booster packs for this set as it was known that this was going to be the final set. There were a whopping 14 Player's Choice cards (with 1 of them being brand new to the TCG, PC6 Kikyo) and 6 Feudal Voice (FV) cards. PC1-PC3 would sometimes have a black box instead of containing a signature and stamp on them. PC4-PC14 would have their normal text instead of the signature and stamp overriding them. PC1-PC6 had only 20 signed and stamped copies of each, while PC7-PC14 had only 10 signed and stamped. That wasn't all though! The FV cards also somehow were missing signatures and stamps on them as well and would have a black box on the card. These were also likely unintentionally inserted into packs due to probably being on the same production sheet as the rest of the set.
Below you will see a comparison of what a Rumiko Creation that is signed and stamped looks like, a non-signature version looks like, and what a black version looks like. The differences are very noticeable, especially when you compare Light Version vs Dark Version! I wanted to use the same card for all 3 but nobody possesses the all 3 versions of any RC card. As such, this will have to do!
Q: So what cards exist as what exactly?
A: So, to summarize:
Keshin:
FV1-FV6: Only signed and stamped copies seem to exist
PC1-PC3: Only signed and stamped copies seem to exist (though an unsigned/non-stamped version exists on an uncut sheet, as does a Dark Version)
Tensei:
FV1-FV6: Both signed/stamped and unsigned/non-stamped exist.
PC1-PC3: Both signed/stamped and unsigned/non-stamped exist (will be a black box on the card).
PC4-PC14: Both signed/stamped and unsigned/non-stamped exist (will contain the normal text of the card.
Rumiko's Creation:
RC1-RC20 - Signed and stamped. Light Version.
RC1, RC2, RC4-RC20 - Unsigned/non-stamped. Light Version. RC3 was not with this group but likely does exist. These likely originated from the "Score Entertainment Vault." Additionally, RC15 and RC16 are on an uncut sheet.
RC2, RC4, RC7, RC8, RC11 - Unsigned/non-stamped. Dark Version. The remaining 15 likely exist but have not been discovered. RC15 and RC16 are on an uncut sheet.
Q: Who owns the most Rumiko Creation cards?
A: Hands down, the answer to this is mirkojaros. He owns 25 RCs that I know of. He has 19 unsigned, 4 signed and stamped, and 2 Black Version. He does not currently posses any RC3, to my knowledge. To note, he purchased all 3 RC's that were owned by Preston Stephenson. inviso currently possesses 5 Black Versions. Funny enough, both mirkojaros and inviso own RC7 and RC8 as a Black Version from Saisei, making them both the only known collectors to 100% Saisei.