Rivkin

Unless there is something stunning about it I would not prioritize that. There are high quality late Bizen pieces but they are rare. Anything suriage post-Nanbokucho incurs significant penalty if suriage; the signature is affected so its an issue. Unless in hand there is something really impressive.... There are better blades to restore.

Applying light from above does not work with nihonto except one specific case which requires significant skill. Safest procedure is to place light source on the side. Or take a light stick and move it around the blade until you find where it makes the nie sparkle. The problem is Chogi was not trying to work in one single Soshu (or Bizen) style. He had basic understanding of them all - Norishige's, Sadamune, Hiromitsu. So there is a lot of variation. But he also has "typical style". First and foremost there is nothing coarse. Hamon is nie based, but nie never gets above certain size, its very fine grained. sunagashi of almost exactly the same nie particles that are not ko nie, but not large either. Same about hada - very bright, filled with ji nie, but very consistent and fine grained itame, can be mixed in with mokume elements. Again, nothing really breaks out - chikei, mokume it sort of blends in. There is tobiyaki/yubashiri but it does not get to full hitatsura. Depending on polish you can more or less clearly see nioiguchi - not as bright as with Go, but better than many Soshu. The outline of hamon does not follow Mino with its togari or Hasebe, it has a certain Bizen feeling to it but at the same time is much less periodic and the shape of gunome (choji?) is much more varied along the blade but at the same time the hamon is always wide. Kencho and Chogi can be very similar and attributions sometimes go back and forth.

Different light direction can really affect hada appearance, but still I see the hada which is coarse with visible lamination in places, but otherwise has this dense, grey look... No color changes, utsuri, no ji nie, just greying itame. Nakago can be late koto, sugata can be late koto, but this very distinctive periodic choji gunome, each having exactly the same very solid and single tone, but relatively bright appearance - does not look like koto. Its a shinshinto style and something that quite a few practiced at the time. Same about hada, I don't see the variety one expects from koto, to me its more modern.

shinshinto, not the first tier smith influenced by period's Bizen school - Yokoyama and Chounsai. Poor quality jigane (100% dense).

Dewa Daijo Fujiwara Kunimichi is great. Like his work, and on occasion you can buy his suriage things which used to go as first rate Soshu pieces and now are discount mumei shinto which many will tell you one should not collect. I occasionally do, still alive, so its not that dangerous. Here ze main issue is ze fotografier has placed the light source where it should not be: perpendicular to the blade on top of it - the worst position. I bet he does it to all his blades - some standard setting that is convenient to operate... A few things you want in Kunimichi: Really standing out zanguri hada. The images here are bad and we don't see anything good here, so assume its in the very least is not great. Wonderful Soshu hamon in strong, sandy nie. Here we see... white hadori. Nothing else. There might be something, but its surely hadori suffocated. So the images are definitely bad, polish is most likely bad, nothing really great is showing and we come to the final caveat - recently some shinsa teams slap Kunimichi on any Soshu suriage shinto piece. So you have great Kunimichi sitting next to "Kunimichi" with the same paper but 10% of quality... thank you judges. Below is the blade I believe is Kunimichi. Ze papers say Naotsuna, but characteristic angled whirlpool hada... classic Kunimichi.

I would say choji and notare/midare etc. I am not great at terminology, but: Theoretically most hamon can be called midare, practically one says it to accent the variation in hamon. When the variation is intermittent widening and narrowing its notare. Combination of notare and choji, with distinctive groupings of choji is something one starts to see in Nanbokucho Bizen in particular. This is much later but it throws back to those basic forms.

Thanks a lot, see this one. we had a discussion recently whether Sanekage, Go or Tametsugu can be applied to tanto, shame on me, should have checked instead of assuming!

That's as close to Darcy's writing style as I've seen. Apologies, personally I could never relate to it. It carries an aura of certainty, branding and a signal that the blade being described is superior because kantei is estimation of quality rather than specific features. I am no alien to partisanship in this matter since I own quite a few Tametsugu. The problem at the core is Tametsugu in Edo period oshigata was a rather specific person - a minor Mino smith, very similar but maybe lesser compared to Kinju, with Mino togari and at times specifically Mino jigane with masame in shinogi ji. There are no oshigata of signed Tametsugu blade from his northern pre-Mino times, nor is there is a known signed example. Its Mino period. There was not much reason to attribute blades to him since Kinju and Mino Kanenobu were better recognized and left a number of signed blades. Then little by little these attributions to Tametsugu and Sanekage kept expanding and what was at first minor now became a huge chunk of circa 1330-1380 Soshu. Sanekage remained strictly Uda-ish Norishige, but Tametsugu became almost everything. One of my blades is ex-Norishige and is the only Tametsugu tanto known (mumei, what are the chances). It has too sharp a gunome to be fully comfortable its Norishige or Sanekage and too matsukawa hada to be Kamakura lineage. Is it Tametsugu really? Without any signed period examples its a conjecture. But what other name one could use? There are simply non available or recognized.

Most likely it is shinto, from 1650-1665 judging by sugata - it maybe not 100% kambun but getting there, there is also characteristic widening in the lower half which is also borderline Kambun-like. Wide nie hamon in notare can be in theory Yukimitsu but since it is not even close, shinto, not too many other options. Problem the style was not exclusive to Yasutsugu. Generally the blade can be a good match, but I would check the jigane - it should really stand out even with light completely to the side, and Yasutsugu nie tends to be high quality, nice sandy kinsuji in places. My other suspicion is it can be an early work by the third generation. More precisely is impossible to tell without many high quality photos.

Per se Japanese have little appreciation of old objects conservation in a white men's sense. They see a cultural object as continuing its existence and function until its demise rather than being fixed in a specific state. Its most obvious when looking at the architecture - the "gold pavilion" is one of the most iconic Japanese buildings yet today its very different than it was 100 years and 100 years ago it was very different compared to Muromachi. Wooden architecture, straw elements as part of floor and roof construction means each building is continuously rebuild, maybe couple of beams can survive the entire lifetime, but otherwise when it says "this is 1000 years old" it usually refers to the institution, not exactly this building in exactly this place and in exactly this form. There are relicts where >50% is something very old, but they are rare exceptions. City of Hiraizumi is a great example - in the west this would not happen and if it would, it would not be considered a national historical treasure. In Japan its seen as such. By the same token as long the blade's function and purpose are exactly retained as original, the need is not to preserve the original polish as part of the sword's history, but rather repolish it to fit the contemporary perception of what today is an appropriate appearance for this blade. By the same token Japanese give very little consideration to any second tier (i.e. not properly sealed and written account by government entities) historical provenance associated with a blade; by default they believe such information is faked and therefore unless its confirmed with zero doubt by a modern authority it does not even enter the radar. At the top tier the original Daimyo receipt from Meiji period solicits only shrugs and sniffs, while modern sayagaki of unquestionable authenticity claiming the same provenance is treated as end of discussion argument. For a white person its weird since it is old documents which are needed to confirm the old provenance; for a Japanese its natural since the qualifications of the modern authority are accepted, while old things remain uncertain.

Good pictures of activity taken with dedication to showing the activity would be helpful. Otherwise: 1. EUR 20,000 for o-suriage Yasutsugu-2 is crazy money by about a factor of 5. Effectively its a price of very good signed example. Unfortunately France is its own world in everything scientific and cultural so anything is possible. 2. Shinto can be difficult to kantei and I personally seldom kantei shinto. 3. Broad suguha-notare with nie hotsure is indeed something Yasutsugu well known for. If its second generation the jigane should stand out.

The writing style/nakago is very recent, can be WW2 can be later.

Bizen boshi is photographed by laying down the blade and pointing light from a side (i.e. sword on the left, light on the right), the light source needs to be about 2-10 inches above sword's plane and as far on the side so the boshi does not get blasted by too much light. Then boshi comes out as dark contour.

I would bet 3 to 1 its a high class imitator, but it is ko ichimonji style.

No, its very consistently shows the same thing.