I think the reason I thought for a few years about making a blog was entirely so I could discuss this term.

Den is one of the smallest, yet most confusing things to show up in authentication papers. There are many assumptions that come along with this word, and it is in the end important to understand what it means and how to deal with it.

The way you would normally see this on origami is something like this:


This says: katana, mumei (den Yukimitsu)

The literal meaning of the 伝 character is tradition, and we use that meaning when we say something like Soshu-den (相州伝). When used as a prefix to the the name of the maker of a blade, it is modifying the attribution somewhat.

A weaker translation of this word is school, and this is not a good reading in this situation because it implies that the attribution is to anyone-but the person named. For instance if we read Den Yukimitsu as meaning Yukimitsu’s school there is an implication then that this is made by Yukimitsu’s students and it’s not what this means.

Furthermore, if the attribution is actually to a school, say, Ichimonji, if you read Den Ichimonji as Ichimonji School it would mean nothing different than an attribution directly to Ichimonji (as it is already a school). There would be no point in saying Den Ichimonji on an attribution if this were the case, since it wouldn’t add any specific meaning to say Ichimonji School School. Since we do see Den Ichimonji used, we need to better understand what the judge is trying to state when using this term.

Here is a quote to get us started, from Bob Benson’s recollection of his conversation with Tanobe Michihiro sensei about den. 

Benson: What does “Den” mean in the use of “Den Rai Kunimitsu?”

Tanobe: The “Den” means that that sword is almost a Rai Kunimitsu. We use it meaning “almost”.

Benson: You mean the sword is lacking, so it is almost a Rai Kunimitsu?

Tanobe: No. That is where the misconception by collectors comes in. In some ways the sword might not have all the traits produced by that smith, but most of them, so we say “Den”. In this case it may be lacking somewhat, on the other hand it might have all the traits of a Rai Kunimitsu but in addition, it has work that is better or could be considered his best work. In this case it displays greater ability and qualities not normally seen in the smith so here again we use “Den”.

What den isn’t

The major take-home is that den does not change the attribution. If the attribution is to Rai Kunitoshi, with or without den, the attribution is still to Rai Kunitoshi. This is generally the sense in which we see it used on authentication papers.

It doesn’t mean probably not, it doesn’t mean by one of his students. It doesn’t mean school and it doesn’t mean less worthy. It doesn’t mean lower quality.

What it usually means

I have taken to explaining it to people as it means “plus or minus five percent vs. the textbook work of the smith.” This embraces Tanobe sensei’s statement above as reported by Bob.

This makes den a general purpose fudge factor that requires some context to understand.

In practical matters, making an attribution (especially with a panel of judges) means getting a group of people to agree on one idea. Always easy, right?

If you have one judge arguing for Kanemitsu and another arguing for his student Masamitsu then there is potentially a resolution of the argument by offering up a den Kanemitsu or den Masamitsu attribution depending on where you can get the judges to agree. This covers both senses mentioned by Tanobe sensei above. Whichever smith represents the best answer that everyone can agree on, den modifies that answer to provide a little bit of fudge factor and safe harbor for the people making the answer.

It would not be correct though to take den Kanemitsu to always mean “Kanemitsu, but a little bit lesser work” as it might in this example above. It means “Kanemitsu, but a little different work” and that little different could be little-bit-plus, or little-bit-minus or sideways in skill. In the example above, it could be used as a dispute resolution mechanism by bridging the gap between the two opinions. Ultimately the judges will settle on the most likely answer to the question of “Who made this?” and that is the name that will go into the attribution.

Older use

In trying to get a greater level of understanding of den, it helps to look at some older books and papers. If you look at the Kokuho (National Treasure) blades from before WWII, all of the mumei (unsigned) works are listed as den-something-or-other.

There are no direct attributions when the work is unsigned in the old Kokuho. And if any part of the signature was cut off, or worn away, then den was added to the document.

This is the most simple and clear use case: whenever the opinion of a judge weighs in, den is used in the document. It signifies a rational judgment and expertise being used in order to come to a conclusion. If the blade is fully signed, then the blade is a component of the textbook, to which unsigned or partially signed work needs to be compared. As such, these do not have den in them. The Honebami Toshiro is a meibutsu blade and famous for a long time as a Yoshimitsu, and it is recorded with den when it held the status of Kokuho.

The Honebami Toshiro (den Awataguchi Yoshimitsu)

In this sense it is apparent that den was simply being used simply to mean “attributed to. It should be noted that high level Honami attributions in the old Kokuho were treated the same as if they bore original signatures. I think in this case, with the understanding that the Honami supervised the shortening of these blades.

Since we have kind of wandered away from this simple use of in modern times, some confusion has entered the picture as a result.

When it comes to Japanese swords, we often have many unsigned works and very few signed reference pieces to refer against. Sometimes we have no signed work at all, and the attributions have to be done on the strength of old attributions handed down to us from 300 years or more ago. We use books as well that have text descriptions and drawings, both of blade structure and of signatures. Together, these with the older attributed blades, they give us a template that can be used to attribute others to these makers. The smiths Sadamune and Go Yoshihiro have no signed work at all at this point in time, however they have good sized bodies of old attributed works, some of which are famous, and these provide us a template. Because there are no signed work, all works by these smiths should come with den, and in fact my opinion is that all mumei work should be considered to be den in keeping with older use of this term.

We don’t see den on older Honami papers to my knowledge, and in more modern attributions judges have expressed their certainty by making direct judgments on mumei work without expressing den at all. And therein lies the problem, that people want to believe in formula and so start assuming that a work stating den is inferior to one that doesn’t.

The following two examples show blades that were Juyo and graduated to Tokubetsu Juyo. Both are great swords attributed to Norishige and I got to handle both of these. In the process of being upgraded, one gained den and the other lost den. It shows that there is no real reliable measure for when this word will come into play. In this case just different sets of judges at different times equate to den or no den. 

Norishige gains den at Tokuju

Norishige loses den at Tokuju

Honami attribution signatures erase den

In the case of some attributions direct to a smith an attribution is sometimes made directly on a sword via shumei, kinpunmei, ginzoganmei or kinzoganmei (red lacquer, gold lacquer, silver inset, or inset gold inset attribution signatures).

Another important thing to recognize is that when a blade carries an attribution signature on it, it automatically loses den if the attribution is agreeable in almost every case. That is, den as a modifier just stops existing in these cases.

This may carry forward from the understanding that the gold attribution signatures are not just an opinion the way the papers are, but originally were an attestation that the signature was there and then removed by suriage. This may carry forward then to Honami who made these gold signatures without witnessing the original.

I found only a few examples where den was added to a Honami attribution mei by the NBTHK. Sometimes they are worn away attributions or some of the lesser Honami. However one was on the Oshima Yukimitsu which is one of the swords in the Kyoho Meibutsu-cho register (the most famous swords of the Edo period).

In this case the blade passed Juyo and I think Dr. Honma believed the work to more likely be Sadamune so he only accepted the old attribution with great reservation. Because the blade is so famous there was no way to propose altering its history by removing the attribution. More on this in the next section. But the blade lost den when it passed Tokubetsu Juyo as above so this “oversight” was rectified. This blade was also a tanto and made mumei originally so there was no signature to observe in the first place, as with suriage katana.

There are another three Meiji period inscriptions among the Juyo called shu-sho and don’t have a Honami judge associated with them that have den associated with them. Two more actually exist where the attribution has been completely rubbed off and is no longer legible: these took den during their attribution by the NBTHK but they no longer have a mei on them, just some flakes of ink. These are considered separately from attribution mei it seems, regardless the number of these even is very small.

Honami papers don’t stop den

Anyway once the Oshima Yukimitsu lost its den, this means that there are zero Honami attributed blades on the nakago that have received den by the NBTHK. So the relationship here is pretty clear.

We know for sure it has something to do with the act of inscribing, because there are at least 37 blades with Honami papers that still received den on their Juyo papers. So it’s just not out of respect for the Honami, it signals that if they put a signature on the blade, there is something different we’re dealing with than simply an opinion on paper. It is more tangible and reliable at least where it comes to issuing the den tag on these attributions.

The case I am making here for you overall, is that to DEN or not to DEN can in some cases be a bit arbitrary from a modern standpoint, and as a result, I think most of the time you can safely ignore it and use your eyes and brain instead.

Even one Motoshige with papers from Honami Koon and the first four characters of the signature became den when it made Juyo under Dr. Honma. This blade is about as sure a thing as one can get without seeing the last two characters. This blade is also a meito with the name Omori Motoshige so is a well regarded sword. Why they decided to put den on this, I don’t know as it looks very much like Motoshige to me and they have 66% of the signature to check, but it is in the third Juyo session so was very early and some of these early sessions can do unusual things. I think today this blade will qualify for Tokuju and like other examples will lose its den when it passes eventually. If it is not lost.

The Omori Motoshige (den Motoshige)

Den as partial disagreement

In the case where a modern judge does not completely agree with an attribution, they could insert den on a sayagaki. This is rare, we do not see it in the NBTHK Juyo papers other than with the scant shu-sho as above and I have seen it only once with Sato Kanzan. It that case it may be Meiji period shu-sho again being the issue.

More likely is that the NBTHK will disagree with such an attribution to a smith by attributing directly to the school in the Juyo paper. This is not a full disagreement so the attribution signature can be left to stand.

This also shows that den does not literally mean school since, for instance, the NBTHK will depart from an Aoe Sadatsugu attribution mei to Aoe in the commentary for instance but will not use den. The Honami used Sadatsugu as a flag to indicate the highest level of Aoe work, by attributing it to the most revered Aoe smith, so this attribution was meant to be taken figuratively not literally.

In another example, Masatsune or Tomonari could be watered down to Ko-Bizen in the NBTHK’s judgment. These are smiths of the Ko-Bizen school so the NBTHK is saying yes, the attribution to these smiths are one possibility but it is not agreeable to narrow down to them specifically and rule out other smiths of the school. Again, no den is used to do this but simply an attribution made to Ko-Bizen with a notation that there is a shu-sho to Tomonari added to the blade.

This toning down of an “out on a limb” attribution can also be seen frequently with Masamune. For these the front of the Juyo paper will cite the attribution signature of Masamunwithout using den but the commentary on the back will say something along the lines of “the attribution requires further study, yet the blade is certainly the work of a high ranking Soshu smith.”

This is of course a mild rebuke to the author of the attribution, without denying it outright, and the reader needs to understand that the NBTHK believes several Soshu tradition smiths could have made this particular blade when this kind of language is used. Likely candidates are Sadamune, Shizu, Yukimitsu, Norishige and Go Yoshihiro. These are all master smiths, and the style of the blade should lead the advanced student to the thoughts of the judges and which of these other suspects are being included in the judgment.

Depending on the wording, it could also be an upgrade of an attribution thought to be too conservative or out of date with the times, for instance from Yukimitsu to Sadamune or Masamune.

The takeway here is that if you lean on den as a simple and literal formula, you could come to the exact opposite conclusion as is laid out in the commentary of the papers.

The devil is often in the details. If you are confused with any attribution, you need to study it more carefully or ask someone for help. There can be some reading between the lines on a case by case basis involved.

Den as tentative judgment

Den can and is used in some other minor cases. These are when a blade is signed or attributed and some doubt is desired to be expressed about the judgment. This is different from the case of a mumei blade and is what happened to the Omori Motoshige above.

If there is an original signature on the blade, and if the judgment is thought to be sound but not yet fully studied then it can be accepted at face value and some hesitation offered using the den phrase. This is done as a tentative judgment, to allow some room for reversal. In this case you can read this as a to the best of our knowledge this is correct. 

The following item is a signed by Sanenaga, an important smith but is cut just before the final characters of his signature. As such there was some doubt when it passed Juyo and this is a common use of den on signed pieces. When this blade passed Tokubetsu Juyo the den was removed which indicates the original uncertainty was minute and then resolved.

Sanenaga (partial signature, losing den)

Please do bear in mind that it makes a lot of sense to be conservative at first and then give things some time to settle, as it is more difficult to introduce doubt at the end of study than at the beginning where it should be.

Attributing to the school

Den Muramasa could be a bit more confusing example to use, because Muramasa is both taken as an individual smith and as a school. If we mean an individual, we would assume someone is referring to the most famous smith of the line of smiths bearing this name. If someone were to say Den Muramasa on a sword it could be taken in either sense. But since there is an alternate way of saying it is being attributed to Muramasa’s school by saying Den Sengo or Sengo then it is more likely to be tightly bound to the Muramasa smiths without enough characteristics to separate between them. It could be followed by an individual judge making a call on a sayagaki to Nidai Muramasa (second generation) for instance to resolve the ambiguity.

In the case of a smith like Shizu there are several ways a judge could make a wide ranging judgment.

Shizu is used for work that is clearly work of Shizu by fitting expectations perfectly.

Den Shizu would be taken to be work of Shizu Kaneuji plus or minus a bit. On the plus side, someone might argue it could be Masamune! On the negative side, someone might argue it is by one of his students, the Naoe Shizu group. Or it could be surely work of Shizu just plus or minus a small feature or two. Which of these situations needs a case by case analysis. But overall, it still means that the best possible answer for who made this blade is Shizu Kaneuji.

Den Ichimonji is not something that we would expect to see, but if we do, it may mean that Ko-Bizen or else Mitsutada or Nagamitsu or Moriie may be alternate good answers (but not nearly as good as Ichimonji).

Den Yoshioka Ichimonji you could take to mean it certainly is Ichimonji but the style is close to Fukuoka too so Fukuoka Ichimonji is another possible good answer. Just not nearly as good as Yoshioka Ichimonji.

By now you may be getting the hang of den.

Refining a den attribution

The reverse can apply as well in the case of den or a school judgment. In this case the original attribution could be to den Ko-Bizen for instance, and then Tanobe sensei may write a sayagaki to Masatsune. Another common thing to see would be to see a paper issued to den Ichimonji and then a sayagaki done afterwards more specifically to Fukuoka Ichimonji. I have had a Yamato Shizu that Honami Nisshu specified this should be taken to mean Yamato Shizu Kaneuji. This didn’t involve den but it is a similar case of refining a judgment that could be open to interpretation otherwise.

In these case the judge making the sayagaki is agreeing with what came before in the papers, and then issuing a more specific judgment. Den or a school attribution could have been used previously to settle differences amicably and come to a joint judgment, and then an individual judge states his case after on such a sayagaki. Or in the case of Yamato Shizu simply clarifies an ambiguous phrase.


Overall, there is some context and knowledge required, but I think the best way of understanding this term is to view it a little bit as a conflict resolution mechanism that allows judges to come to an agreeable conclusion with current or past judges. It helps for preserving face, to agree or disagree without explicitly doing so, or to mark a blade as having a little bit more or a little bit less than normally expected.

As Tanobe sensei points out, it doesn’t mean a blade is necessarily better or worse than another with no den on it. So, you shouldn’t worry too much about it provided that it’s not being used to distance from a prior judgement that you want to believe in.

I’ll leave you now with Bob Benson’s words of wisdom.

I guess it gets back to what I was taught years ago. Forget the appraisal and look at the sword. Be able to hone your own abilities so that you can judge for yourself. — Bob Benson