Hoshi

Interesting. I decided to follow two rules : Every new sword higher quality than the previous. Every new sword by the mentor or inspirer of the previous. Eventually this will lead to a very narrow and long collection with a 3-10x price increase from the previous. For now I have : High quality shinshinto blade (some malevolent man decided to weaponise it by removing the signature, punched another mekugi ana, and aged the nakago to make it pass as Koto, hence its basically worthless) by a sai-jo Saku shinshinto smith. This blade which my was first love was in Soden-Bizen style. So that sets a direction towards Soden-Bizen direction. My second blade is by Kensho, and the third will be by Chogi hopefully. This way I have a horizontal collection of the soden-bizen school. After I reach the last nod of Soden-Bizen, I branch out to seek two very prototypical blades of Bizen and Soshu. For now that's where I am in my thought process. If its unachievable due to me being unsuccessful at grinding cash then so be it, it will stay where it is. This is a luxury hobby which I see as a reward to motivate me to do well. Swords are not investments alas, I fully expect to be paying the renting cost before it moves on to the next owner. Purchases are made with the conservative notion that 20+% of the money invested will be lost. Unless of course, I manage to partake in some of the money-bleeding auctions from deceased collectors where bargains are had - but given my "detection rate" this is unlikely to happen. Hence, boutique purchase with all the overhead that comes with it.

Hello Darcy, This goes against the general saying of "form follows function" - which I've often read, if we compare koto swords to watchmaking complications The notion that customers were after swords that will afford them many re-sharpening opportunity is something I didn't give much weight to. It's interesting because then you'd expect the Hamon thickness to coincide with strike areas, and this is often what you see. Shallow Hamon at the base, wide hamon in the middle/upper segment. Both the re-sharpening factor and the creation of a geometry that would be bend at the base then coincide. I agree that the mongol stuff is mostly overhyped in terms of actual battles. However, the psychological factor I believe at the time was monumental, and spawned levels of anxiety with regards to military preparedness (and hence, quality of arms) that was unheard of. The fear of another invasion attempt was very real. This is an existential threat and you need to do the rational thing. Study the tactics, arms, and armours of your foe. Reproduce them if you can and train against them. While this may be unrelated to the fall of the ichimonji it is highly likely that it is related to the trend towards more robust and designs. The more I think about it and the more I think the best way to think of a Hamon is in terms of wave frequencies. If you do a Fourrier analysis on a Hamon you can decompose it into different frequency variations. The repeating high and low undulations are in the high frequencies, while the asymmetry from the upper, middle, and bottom segment are low frequency variations. What sort of insights can be derived from this formulation I am still uncertain, however this can be very for the purpose of creating a stress simulation. Unfortunately I'm not a stress engineer and getting all the parameters right is probably far above my punching weight.

Tempting.

Hi Allan, Thank you for your input. It's because breaking is such a disaster compared to the other outcome you describe that surely that was the number one priority to be optimised. Edge chipping is no big deal in battle. A broken blade tends to cause death. And we know just how shameful it was for a smith to have his blade break in usage, the ultimate dishonour and for good reason. What you mention (Cold weather performance, cross-sectional profile, material availability, blade length and shape) all of these are parameters which are featured into the odds of breaking/bending calculus. The singular goal was to create a blade that cuts (hence, hard) which at the same time does not break (hence, bends). Hello Carlo, The amount of broken blades against reinforced boiled amor was such that is spanned a mini revolution in sword geometry. I agree that sword smith classification in the koto era correlates with durability - and presently I'm focusing on the top smith to see if I can find patterns in hamon formation made specifically to mitigate break in favour of bend. As Arnold pointed out, the wild ichimonji hamon failed w.r.t to durability. This corroborates the notion that unstructured midare is poor design. The key to a successful midare was perhaps the structured midare (shallow towards the area of high stress) - maybe even superior to the descending suguha (suguha that tapers off towards the habaki). Because otherwise I just don't see why midare even came about during the Koto period, during which battle functionality was the prime and only criteria. As for the Ichimonji, I have a theory. Because of the unique arrangement with the exiled emperor, the smiths therein were engaged in something closer to a beauty contest compared to a functionality context against hard targets that would damage the sword regardless. But I digress.

Thank you Arnold, this corroborates my intuition. Studying hamon geometry lately moved my inquiry away from simple midare versus suguha, towards structural soft areas of steel incorporated into the design as PoBE. The Hasebe sword and the Kuniyuki illustrate this. How do I even find your reference... I wish such things were indexed by google scholar. John, soft medium was the wrong word. But body and bone do not pose a large risk of break if the strike is well executed, and it was given that it was performed by professionals. A Kabuto, plate amor, or mongol reinforced leather, or another sword, are a different matter in terms of stress and risk of catastrophic failure. This is why I don't think the wazamono index is appropriate to measure durability. It's a different thing. Michael, I haven't found any particular in depth discussions about the physics of stress applied to sword manufacture besides the oft repeated observations of Masahide. Large Shinto hamon make brittle swords. There has to be more than that to it. I'm starting to think that the midare geometry as designed by some master smiths of the koto period were specifically made to increase durability as per the argument laid above. As a side argument, if the theory that the base of koto swords were (in some cases) designed as PoBE, this would be another argument devaluating Suriage swords. We keep hearing about "true shape" being altered, and in some minor accounts balance. But in fact, we may be facing swords that are largely inferior to their ubu counterparts due to the added brittleness.

At this price keep in mind it wasn't produced in Japan. Commissioned in China. EDIT: for the price it looks great :-) the gold is a tad too gaudy for me, but the design is nice.

To go back to the Hasebe, the theory seems to hold. Almost UBU sword. http://www.sho-shin.com/hasebe-kuninobu3.jpg Area of shallow Hamon at the base designed as PoBE. Of course we'd need more data points from the top smiths with excellent repute for durable swords. I am not sure the "wazamono index" is fitted to this - as it was not created as a measure of durability but of cutting ability in soft medium. As to swords being designed to absorb impact through vibration, of course I agree - but there is a point of failure where the vibrations alone cannot absorb the stress and this leads to catastrophic failure (breaking) or, if well designed - a good bend.

I think I have a theory. Let's assume a sword is struck. If you have a even structural rigidity, the point of break (PoBR) is the same as the point of bend (PoBE). If you want to maximize the odds of bend at the expense of break, you should voluntarily introduce a PoBE that is different from the PoBR. If you have an undulating hamon, you're basically distancing PoBE from PoBR. This means the sword will take a bend rather than a break with a higher probability as the PoBE will absorb impact. Undulating hamons will create multiple dissociated PoBEs at each shallow valley. Furthermore, if you know don't know where the impact occurs and you're unsure about the area of likely maximum stress, you're better off creating multiple PoBE compared to just one. Moreover, a bend could be distributed over multiple PoBE rather than a single one, further reducing the odds of shattering the sword. If we take the Kuniyuki, The hamon geometry at the base of the sword is clearly designed as a PoBE. For the Hasebe, let us remember that the sword was massively cut down from its original size. There probably was an area of shallow hamon at the base designed as a PoBE. If we assume that indeed both swords have a PoBE at the base, we can further observe that the upper segment of the sword has a more shallow hamon as well, perhaps another PoBE designed to absorb kissaki strikes?

Hi Ken, thanks for your input. I'm not referring to post-unification blades - but old swords. Steel in the hamon is harder than steel outside of the hamon. The harder the steel, the higher the likelihood the blade will break and not bend. If hard steel is not equally distributed, so is brittleness. Hence, where the hamon is deep, the blade is more brittle. Masahide observes and records that large hamon make for brittle blades - but my inquiry is not about these exagerated shinto hamon, it's about the koto blades with undulating or uneven hamons. From a purely engineering perspective, why would you favor an undulating or flamboyant hamon rather than a simple but sound thin suguha? I presume it's through trial-and-error, and that for these traditions it simply "worked" - but I don't understand the physics of this at all. One explanation is that it was already at the time, aesthetics that prevailed. But this goes against the common saying that swords were foremost designed around function at the time. I must be missing something and this is why I'm puzzled. Let's illustrate with some of Darcy's incredible pieces- Take the Hasebe/Chogi. Hamon is thick in the first segment, shallow in the upper segment. This was a massive sword and durability was critical. There is no way this wasn't done for functional purpose by the smith. http://www.nihonto.ca/hasebe-3/index.html Take another masterpiece, the Rai Kuniyuki. Again, you would assume that Kuniyuki designed the uneven geometry of the hamon for functional purposes. http://www.nihonto.ca/rai-kuniyuki-2/index.html Here we have the exact opposite. Thick hamon in the upper segments, shallow in the lower ones. So we have two great smiths with a complete opposite take on hamon geometry. We can notice that the Hasede (on top of being massively thick) has no taper, while the Kuniyuki has a slight taper. But would such a difference in taper warrant the completely at odds hamon geometry? Why? Why not opt for a fine and even suguha, like so: http://www.nihonto.ca/omi-daijo-tadahiro-4/ I must be missing something. I doubt this is purely "artistic freedom" and has to be product of trial-and-error and data accumulated from customer feedback over generations. How do swords even break? Do they break at the point of impact or point of maximum tension (lower close to the base)? I know very little about material stress, but I assume its the latter. The diminishing suguha towards the base would then make perfect functional sense, and we could surmise that the optimal hamon has this shape (I faintly recall reading somewhere that kotetsu tended towards diminishing hamons, and he was an empirically-minded smith). But then, the Hasede doesn't make sense...

Something that has been nagging at my mind. Perhaps a naive question but I can't seem to come up with an answer. Why the wavy midare hamons? If you want to maximize structural strength you need to ensure stress is evenly distributed. From an engineering perspective this means suguha hamon does it best. Why the wavy stuff in the Koto period? (Shinto is a different story as aesthetics begin to trump functionality). Straight and shallow suguha minimizes risk of catastrophic failure assuming the blade has no taper on either dimension. Now, I figured out smiths probably knew where impacts are the most likely to be had. Even if you derive some sort of probabilistic heat map of the odds of structurally threatening impacts, you would then again do a variant of suguha to ensure stress is minimized on this surface. Wavy midare adds spots of brittleness to the blade, where the hamon is deep. Why? Some elements I've been considering which may lead to unforeseen non-linearities in impact stress response. The hada gain orientation usually correlates with midare versus suguha, why? Some smiths have produce differential thickness of martensitic crystals on the valleys compared to the apex of the waves. The orientation of the martensitic crystal could change as a function their point along the curvature, which may change structural properties. We're assuming frontal impacts. How does force reverberate across lateral impacts? More broadly, how does impact vibration contribute to stress? If someone has an engineering simulation that would be just wonderful. It's hard to imagine nobody tried to do it. Software to model stress on steel of differential hardness exist for sure... In fact is someone did come up with such a model it would be fantastic to see what the model predicts as optimal structural form against how famous schools designed their blades.

Very interesting however the argument hinges on a key assumption... What's the correlation between number of sword accepted to juyo per session and number of Tokuju upgrades of those same sessions? if its very high then we can use the amount as proxy, but I would expect that its not the case. Early session probably have a overwhelming conversion rate compared to latter ones. For various reasons I'm somewhat skeptical that it's a very good proxy at present. For instance, I do not believe session 61 Juyo are much better than session 57. Since you do not know the amount of swords submitted (or do you?) to calculate the pass rate, it's hard to say whether a high output sessions are due to low standards or high inputs. And even if you did, the problem of the average input quality still looms. You can avoid these confounding factors if you get the Tokuju conversion rate per juyo session then you should get a good idea of how much you can derive the ballpark value of a sword from a given session. Have you assigned a unique ID to each sword such that you can track how many have upgraded to Tokuju per session? That would really be fantastically informative. I understand however that the work involved in attributing a unique ID is pretty daunting by hand (and supremely annoying...). But if you filter by smith with some measurements you could get a pretty good guesstimate of what went where. And this can be automated such that the search automatically goes through all possible sets to find a match, or give you a degree of match such that you can incorporate uncertainty into the ID, looping over the 900 or so Tokuju. That way if the match is uncertain you can give it a lower weight into the calculation of conversion rates.

I concur. THANK YOU! I just devoured everything and now I want more...

Another one missed...

Muramasa blades were banned on pain on death by the tokugawa shogunate. A lot of signatures were either erased or replaced in this time in order to hide the true maker of the blade. There aren't very many makers for which a fake signature is used to camouflage a higher quality blade from unwanted scrutiny...

Smells of an elaborate fraud... I absolutely cannot see most of his "Masamune patterns" Videos were posted 8 months ago, and sometimes years ago. In that time I'm sure a few masamune experts carefully looked at them, and concluded it was most likely a fraud. Still, the legend is alive. The first thing to do would be to compare the exact geometry of the Oshigata with the blade. I don't see this anywhere... However, Masamune or not, the blade does have a lot going for it under the surface. Bright chickei and some probably sumptuous activity. I surmise you could have a similar result with the likes of a good Shizu in need of polish. EDIT: and indeed, it's an old fraud. https://www.reddit.com/r/SWORDS/comments/2fbfv4/youtube_user_fiddlin4you_claims_to_have_the_lost/

Please add me to this event and let me know how I can pay the fee.

Truly amazing, the activity is just unbelievable. Thanks for pointing it out.

the website states "the sword is not available for purchase as it sold to a client before posting" Goes to show you just how much demand there is for such treasures...

Fantastic thread! I need a head bucket for the living room I must just convince the wife... On another note, something that strikes you immediately in Japan is the sheer obsession they have with wrapping things properly. I've had two large antique piece of Japanese furniture shipped to my country, and the company built a box out of massive wood for each. Not counting the five layers of covering inside and outside...It took me a day to clear the package. Unbelievable. In Europe you're lucky if they add a sheet of Styrofoam inside cardboard.

When he says "memorizing hamons" - what exactly is meant by this? What are the characteristics that are memorized? I could think about nie/noie-guchi thickness and consistency, types of frequent activity, shapes and depth. But there seems to be so many, surely there is a hierarchy within these elements...

Very nice. Can I send you a few for the same treatment? How much you charging ?

Hi all, I'm currently in contact with a custom maker of museum-quality vitrines, my idea would be to have one made specifically for exposing Japanese swords - where the bare blade can be exposed outside of the Shirasaya for extended periods of time. The company suggest that I opt for an semi air sealed box (with less than 10% air passage per day) with a humidity monitor and moister absorbing medium to ensure it remains at the optimal levels for iron preservation, but they don't know anything about Nihonto preservation specifically. Does anyone here know about the conditions in which swords are kept exposed in Japanese museums? the humidity level and other parameters of interest? They did however tell me that if I opt for a low humidity environment I should not store wooden objects inside (sayagaki, Koshirae, etc) as the wood may crack. On a related note, what about lighting? What is the best angle for optimal results, and the sort of lighting I should opt for? I'd like to get this perfectly right or not do it at all. Cheers Chris

So the latest polish of the blade has used a clever Hadori masking to "rejuvenate" the Boshi area, is that the conclusion? And AA's Oshigata followed the new hadori line on the boshi, while the Juyo Oshigata refered to true hamon showing in the the old polish?

Point taken

Thank you for all the replies! this is a very interesting thread as it goes to the heart of the where appreciation is to be found, which was precisely my question. I now have a far better idea where to look, and while I still don't really get it, I feel that I've got some of the conceptual keys needed for appreciation. That said, my love for kinko isn't going to go away, don't worry! I find the disparaging adjectives on both sides hilarious. Trite, cheesy and parvenu on one side, charcoal plates, iron manholes, emperor's new clothes on the other...