Mikaveli

There were military swords (collected, possibly manufactured) from 54.5cm and longer. Now, from a strict definitions perspective these were not "wakizashi" (i.e. companion swords to another blade).

The core issue is people seeking objective consistency, from a subjective process. It's clear, from the numbers in the Juyo sessions, certain smiths are favoured - but more than their works would necessarily merit. It's a bad analogy, but it reminds me of the Oscars, and when a famous director makes a new film, all the critics / judges see the emperor's new clothes... Objectively, these works wouldn't receive the same acclaim - especially if truly blind tested.

4.6m yen for a Nambokucho, Juyo tanto... Tempting, can someone lend me 4 million yen! 😂

It's an obvious fake - mono steel and recently, unskillfully cut mei: 山口川子 Yamaguchi Kawako? Kawashi? Poor choice for a gimei, as there are very few smiths called Yama... (山…), and this isn't one of them.

Just looking at one Japanese dealers (TM) website: Tanto price range, 250k - 500k yen (these happen to all be shinshinto). Wakizashi, 350k - 1.2m yen Katana, 600k - 3m yen Tachi, 6.5m - 20m yen. Admittedly a micro-benchmark, but data none the less. If we compared similar era and smith, does it hold that tanto are more expensive? Or, are people just looking at older tanto, more comparable in price to tachi around the same age (and quality/ maker)?

Yes, and (hopefully relevant to the OP) be aware that some less scrupulous sellers will sell a sword in poor condition, but mislead buyers into thinking serious flaws will just polish out (they won't) and downplay how much a proper traditional polish costs (thousands, unless you want to ruin any history or value).

Maybe so, but there's a delta between typical prices and possible prices. Just last year, I bought a sword for $1330 that papered. North of $3000, the search becomes much easier, granted. Just as north of $10k, you can be very particular indeed.

Oh, and in collecting terms buying a wakizashi Vs katana... Nowadays there's a bit of an arbitrary (modern) distinction between them - blades over 2 shaku (approx 2ft / 60cm) are usually classified as katana. But if you find something just half an inch shorter, they'll call it a wakizashi and sometimes it'll be much cheaper 🙂

Just browsing through some of the social media for sale groups, there's plenty of showato/ gunto for c. $1500 up. For older, traditionally made blades I think I saw one for $1600 - so his budget isn't miles away. But north of $2000 is a more common baseline, and obviously up from there. I totally understand the enthusiasm to buy something (anything) to scratch the itch. But I would recommend the OP doing a little more research, maybe buy a book or two, maybe stretch the budget a little - you can find something pretty special - that you'll get more enjoyment out of (after the novelty has worn off).

Is there a living polisher that's ever done a naginata naoshi? Otherwise, I'd suggest it's likely just educated guesswork?

Well, I've just bought a copy of 槍薙刀入門 (Introduction to the Yari and Naginata) - I'm hoping it is introductory level! 😅

Yes, and no! 🙂 You're right that just because there are differences, it doesn't necessarily mean gimei - many smiths changed their mei over time (along with titles, yasurime etc.), and I've seen documented examples where with age, their mei becomes noticeably more lightly struck. But by the same token, some gimei is very, very obvious. My favourite is western copies of kanji, shape based without understanding of stroke order, stops or direction etc.

Still, even if it's gimei, and even if the condition is not great - don't write it off (especially without having it looked at by someone knowledgeable). Any pics of the blade - overall and in detail?

Looks very suspect to me... Assuming it's unpapered?

It's plausible, although I haven't seen it myself (on nihonto). It nothing else has changed, I wouldn't bother sending it to be re-papered - assuming the nakago is still a clear match.