Seems Hans Koga has used this apparent book as a scam.
Paul Martin's page -
https://www.facebook.com/The.Japanese.Sword/?__tn__=kC-R&eid=ARAIWFEVRNzY8BPXcdiCVf8ogJr__M6oo8Blr_Ktd1LcYiZLuZiUiOrPyEWHtotdzaZmwow8tIp9lTVt&hc_ref=ARSGqcU46uACoBszNulDiNr2da2uIQNz2dIYcGCzJm_7_lhxPc1_EQHe8JWss09nrlc&fref=nf
A translated post from Izumi Koushiro -
From now on, we would like to particularly warn international sword enthusiasts to please be careful of the Swedish person who goes by the name of Hansuke (Hans) Koga (Real Name Hans Igelstrom) who currently works as a Tsukamaki (handle wrapper) in Kumamoto Prefecture, Japan. He appears to have studied a little, but is not a fully fledged craftsman. However, because he can speak English, he seems to get some requests for work (from overseas). When he appeared on (Japanese) TV last year, he claimed that he was the only person who could do Higo Koshirae (mountings). As you would expect, the local craftsmen complained to the TV station, and the program was stopped from being rebroadcast. First of all, Mr. Koga was looking after about ten swords of an acquaintance of mine, but he sold two of the best ones out of them without permission and has not returned the money. That is a crime. Since last year, the victims (my acquaintance) appointed me as an agent to pursue Mr. Koga. I consulted with a lawyer, but even if we filed a lawsuit in a civil trial and Mr. Koga did not have the ability to pay the money, it just costs more money such as lawyer fees. As there has been no attempts by Mr. Koga to pay money back, my acquaintance is trying to make his case. Furthermore, Koga Hansuke recently wrote and published a book. He has received payments from customers but has not sent the books. This is a complete scam. Mr. Koga was renting a workplace in a private village run by Tamana City in Kumamoto, but he stopped renting there at the end of March (2020). It turns out that he was only renting the space at the Folk Village, the problem was that they allowed it without properly vetting Mr. Koga. I realize that the person in charge understands that non-Japanese who live in places like the private folk villages will also become a kind of advertisement/attraction. However, I would like to ask those who lend without checking carefully to reflect a little on their actions . In any case, we will pursue Koga Hansuke to stop using Japanese traditional crafts as a cover. This is a notice for Japanese and International swords enthusiasts to be careful. Koushiro Izumi Trustee: Nihonto Bunka Shinko Kyokai (NBSK)