Not sure if this is the one you're referring to, but it was on Jim Kurrash/Albert Yamanaka's articles I've stored on my
HD :
Quoting :
A Tachi signed Bishu Osafune Kanemitsu - Jûyô Bijûtsû
A Tachi signed Bishû Osafune Kanemitsu and dated Enbun ni nen hachi gatsu hi. It was designated Jûyô Bijûtsû on December 24th 1937, and was 3 shaku 4 sun 3 bu long. The JB set number is 666, and the Yamanaka number is 4. This was another submitted by Uesugi Yoshiaki to the Yonezawa police. There is no known photograph or ôshigata of this blade at this time.
The book Shôwa Dai-Meito Zufu by Homma - Kunzan reports that “it was returned to Japan by a friendly American” (possibly by Dr. Compton Sama). The information I had given was “Tachi signed Bishû Osafune Kanemitsu and dated Enbun ni nen hachi gatsu hi. It was designated Jûyô Bijûtsû on December 24th 1937, and was 3 shaku 4 sun 3 bu long. The JB set number is 666, and the Yamanaka number is 4. This was another submitted by Uesugi Yoshiaki to the Yonezawa police.” But Showa Dai-Meito Zufu describes this tachi sword as 3 shaku 7 bu / 93 cm. long, and dated Enbun yo-nen jûni gatsu. It is sword number 230 in that set. The mis-information given was at least partially due to it apparently being the only formerly missing Jûyô Bukasai blade without a photograph. And considering the erroneous information that had been available it was extremely fortunate that it was recovered.
In Shôwa Dai-Meito Zufu Kunzan states “This is one of the three nô-dachi, signed and dated, of Kanemitsu included among the thirty-five blades that had been long handed down in the Uesugi family, descendant of the reknown Uesugi Kenshin. It is true with the three long Kanemitsu examples that they were all made perfectely without any defects in both ji and ha, which testifies to the exceptional talent Kanemitsu is accorded in swordmaking. It is one of the blades confiscated by Occupational Forces and taken to the USA after the last war; fortunately it was returned to Japan by a friendly American citizen.”
The JB set number is 666