Jacques

IMHO, start by putting them in chronological order.

Yasurime and the lack of taper shows that this sword is not from Kanbun era.

Hamon, is choji midare mixed with gunome (look at oshigata). As i always say we see nothing on pictures only the hadori.

I would say Shinshinto rather Kanbun

Could be shinshinto even Gendaito.

Old NBTHK papers = no papers nothing else.

What makes you think it's the second generation? I know these two smiths particularly well, and I know what to look for to tell which generation this sword belongs to.

Mei seems legit, probably a sword by the shodai Tadatsuna.

What do you mean ?

Generally, when a swordsmith takes the trouble to make an umegane, which is not an easy thing to do, it is because the quality of the sword justifies it; otherwise, he destroys it and starts over.

Thank you, but I never give an opinion without having held the sword in question in my hand. I ad I'm not an expert, just what you might call an informed amateur.

Okay, In fact, Hon'ami Kozon does not say that there is only one tachi, but that he has only seen one. Have you had the opportunity to see both the tachi you mention and a tanto at the same time to judge the potential difference in quality? Do you have the knowledge to evaluate such a thing? Personally, I don't, and I trust a real expert more than an ordinary person who claims to be one. I questionned Chatgpt about the number of tachi answer below

Absolutely not but it's a thing you don't understand

You don't know the difference between good workmanship and art.

It's always about zaimei swords..