I recently learned about a prize given out for the first ever Yu-gi-oh tournament in Japan in 1999, a stainless steel normal monster Black Luster Soldier. In numerous online english-language articles, the card is cited as being sold for $2 million in 2013. Here are just a few of the many examples: 1    [5 (linked to by 4)]. (If you google search for the card, you will find 15+ more articles mentioning the card.)
Without exception, the articles claim that the card was listed for the USD equivalent of $10 million, and "rumored" or "reported" to have been sold for $2 million. Most of the articles cite no source for the rumor or reported claim, and the few that do just cite other articles with the same claim.
Example from link 3 above: "It is rumored that it has been bought for $2 million."
The "listed for $10 million" claim appears to be legitimate, as I found a contemporary english-language article mentioning the asking price. But my attempts to find the source of this $2 million sale price claim have come up short. Can anyone find a source, in any language, that either validates/refutes the claim, or that appears to be a likely origin of the claim on the internet?