Geraint, thank you kindly for the summary. I also appreciate all the other answers and comments. I do wonder what you mean by "if it does turn out to be gendaito which puts it into a whole other bracket."
I did read that topic days before I posted my example. I felt that there was no definitive answer. The comments discuss that there is much to learn about Hizen smiths that is unknown, mentioned by Cabowen. I also read it as, there is another name to research.
The comment about 1934 was made by another bystander at the show. I believe he was saying that about the timeframe in which the blade was mounted into the current fittings. Like it was in other fittings earlier as mentioned in the other topic. He was an asian gentleman (and I say this because he seemed to know what he was talking about Japanese swords, I did not) and also said the Tsuba and parts were of the "highest quality and special order." This guy was looking at other swords that were not WWII military related. He said for a WWII collector this sword was very very high in desirability, almost but not quite to the top of the top, and that the polish was the highest level. He said it would be very difficult to find/locate a nicer one.
About the 5 notches. I do see a small division between 2 and 3 of the hash marks. "3" being the number on all the small parts of this sword in its current mounting. Why would they also paint a number 3 on it? I've searched the net for weeks, and no one definitively knows the answer. The answer is always batted back and forth. Also why the 2 holes in the tang? Same as the blade in the other topic. It is hard to see if the blade in the other topic has the notches, but then its also not mentioned.
The old tag that is attached has a previous owners name attached. It has scotch tape in two small spots. The tape has turned a deep orange yellow. Without carbon dating it, I'd guess it was placed there in the 70's or earlier. The owner passed in 2023 in his high 80's. His obituary states that he was an avid collector of antique guns and stuff. Guys who bought good stuff early and held onto it. Not to see the outside world until they pass. This tag is the one that says "Tachi Blade" above "Shin Shinto" in old ink, and maybe that's not correct. The dealer tag is the one that says Edo Period.
All and all, it is what it is. I thank everyone for their thoughts and comments. I purchased this sword because I liked it and I feel there is something special about it. Its super sharp. Sorry for the long winded response. I have few others, but not like this one so its very interesting and addictive.
Burt