After introducing the major points regarding jigane, we come to the different forms of jihada, i.e. visible forging structures.
itame-hada (板目肌): Itame is by far the most common forging structure seen on Japanese swords. There is the traditional approach to merely associate itame-hada with the Sôshû tradition but I think this rigid system of thinking, i.e. Sôshû equals itame and Bizen equals mokume should be taken with a grain of salt. That means from my experience as a translator, and I think I have translated blade descriptions way in the four digits over the last decade, the vast majority of kitae descriptions either start with “itame mixed with…” or “ko-itame mixed with…” This is just about itame/mokume as the traditional associations with masame, nashiji and so on are still very much valid. My tip: It is itame unless you really see some obvious burls, i.e. mokume. If it is a few burls here and there, it is probably itame mixed with mokume and I would only say “this blade has a mokume-hada” if the entire jihada or most of it consists more or less uniformly of mokume burls. As mentioned in the last chapter, we distinguish between ko-itame and ô-itame. The former, i.e. ko-itame, is quasi the “default hada” of the shintô era as there was a significant trend towards refinement throughout the early Edo period (culminating in the Ôsaka-shintô style for example). But it is also common for higher-quality Sue-Bizen blades (i.e. chûmon-uchi) where it might be even so tight that it looks like muji at a glance. A good way to identify a shintô is to check if there is masame in the shinogi-ji (see bottom picture below). So if this is the case, it is safe to concentrate on shintô. But please bear in mind that itame along the hira-ji and masame in the shinogi-ji is also a typical feature of Sue-Seki blades so you might check first if something speaks for Sue-Seki (i.e. sugata with sakizori, togari or fushi elements, shirake) before taking the shintô road on the basis of the masame in the shinogi-ji. Incidentally, it is said that the shintô masame in the shinogi-ji actually goes back to Sue-Seki as the majority of early shintô smiths had Mino roots. That means at the end of the kotô era, Bizen was literally wiped off the map as largest sword production site by the devastating flood of the Yoshii river and this left Mino, and Seki in particular, as leading manufacturer of blades. In short, the early shintô smiths who were hired from there by the newly established domains just continued to work on the basis of their scholastic Mino background. Their successors adjusted to the trend to refinement but by keeping basic elements like masame in the shinogi-ji. And that is why this Sue-Seki element “survived” in shintô times. An ô-itame is typically seen on early Sôshû blades, e.g. Masamune (正宗), Sadamune (貞宗), Hiromitsu (広光), Akihiro (秋広), but also on Ko-Hôki-mono (Yasutsuna [安綱], Sanemori [真守). Well, as there are burls seen on Ko-Hôki blades, they are also described the other way round, i.e. as showing ô-mokume but mixed with ô-itame. Anyay, a hada mix is almost always the case when it comes to kotô and as indicated in my tip above, you just name the dominating hada if you want to nail it down to a single forging structure.
itame-nagare (板目流れ): An itame mixed with flowing or running nagare (流れ) structures is, when it comes to earlier kotô, a typical feature of schools that operated far from the then centers, for example the northern Hôju (宝寿) school or the southern Kyûshû schools and smiths like Jitsu’a (実阿), Miike (三池), Enju (延寿), and Naminohira (波平).
itame mixed with masame (板目に柾目まじり): Well, some kind of nagare is seen at many schools and if the running structures tend to appear in a more linear manner, we usually speak no longer of nagare but of “mixed with masame.” So the above mentioned northern and southern schools are typical for a conspicuous itame-nagare that is the dominating forging structure of the entire blade. A mixed-in masame in turn is typical for all Yamato and Yamato-related schools (e.h. Mihara [三原] and Niô [二王]), but also for early Mino-mono (Kaneuji [兼氏], Kinjû [金重], Kaneyuki [金行]) and the Yamashiro Hasebe (長谷部) school where the masame appears towards the mune and towards the ha. At Sue-Seki schools that are not classically inspired and densely forged, the nagare towards the mune often appears as masame and this feature goes back to the same approach in forging as the aforementioned masame in the shinogi-ji. So what is nagare-masame towards the mune at a hira-zukuri blade is masame in the shinogi-ji at a shinogi-zukuri blade, to put it in a nutshell.
mokume-hada (木目肌): As mentioned above, mokume is when you see true burls. They might appear as larger ô-mokume or as smaller ko-mokume burls. An obvious ô-mokume can be seen for example at Ôei-Bizen blades (e.g. Morimitsu [盛光], Yasumitsu [康光], Moromitsu [師光]) but there is some kind of confusion when it comes to associate mokume in general and ko-mokume in particular as the Hon’ami school of thought seems to apply these terms to what others refer to as itame or ko-itame respectively. (Accordingly, most of the blades show for them variations of mokume instead of itame.) Again, I for my part say for the time being that a hada is itame unless there are some obvious burls and then it might be itame mixed with mokume. So please don’t get too much confused about when it is itame and when it is mokume as it is in many cases a mix anyway. (See bottom picture below which shows an itame mixed with mokume and nagare-masame.) By the way, conspicuous burls themselves are – depending on how you see them – referred to as uzumaki (渦巻, “whirlpools”) or nenrin (年輪) or jorin (如輪), the latter two terms both meaning “annual tree rings.”
masame-hada (柾目肌): A masame-hada is usually associated with the Yamato tradition and indeed blades by the initial Yamato schools and those made by their offshoots and later smiths who worked in Yamato style indeed show in most of the cases some kind of masame. The most obvious masame is found on Hoshô (保昌) blades and on blades by the shintô Sendai Kunikane (仙台国包) lineage. But many other smiths worked in masame, for example the Mito smiths Norichika (徳鄰) and Norikatsu (徳勝), Sa Yukihide (左行秀), Dewa no Daijô Kunimichi (出羽大掾国路), Etchû no Kami Masatoshi (越中守正俊), Tsuguhira (継平), Kashû Kanewaka (加州兼若), and Ogasawara Nagamune (小笠原長旨), just to name a few.
matsukawa-hada (松皮肌): A matsukawa-hada is either an ô-itame or ô-mokume that comes with thick chikei along the layers of the forging structures and that appears as large burls which remind of the bark (kawa) of a pine tree (matsu), thus the name. Such a forging structure is mostly seen on blades of Norishige (則重) and locally related smiths, e.g. Ko-Uda (古宇多) and Kashû Sanekage (加州真景) and later on blades by smiths who tried to emulate Norishige, e.g. Nakayama Shigehiro (中山重弘) and Mito Noritoshi (則利). Also Hankei (繁慶) tried to emulate Norishige although in his particular case we no longer speak of matsukawa but of hijiki-hada (鹿尾菜肌・羊栖菜肌) as his aproach reminds more of the brown edible sea algae of the same name.
yakumo-hada (八雲肌): A very peculiar jihada that is created by a combination of steels with different carbon content, an approach that results in thick and standing-out chikei-like structures. This kind of hada is mostly seen on blades by Mito Rekkô (烈公) and is not very common.
Shitahara-hada (下原肌): A Shitahara-hada shows conspicious uzumaki burls along the center of the blade, i.e. along the shinogi-ji or the center of the ji if in hira-zukuri. But these burls might also appear more towards the ha or in an irregular manner, that means as isolated large burls in places. As the kotô-era Shitahara school followed an approach in forging that resulted in such about centrally aligned burls, the term Shitahara-hada was coined to refer to their most characteristic feature.
ayasugi-hada (綾杉肌): An ayasugi-hada appears as large regular waves and as such a forging structure was the trademark of the Gassan school, it is also referred to as Gassan-hada (月山肌). It was later revived by the shinshintô and gendaitô era Gassan smiths. But an ayasugi-hada or tendencies to ayasugi can also be seen at the Hôju (宝寿), Môgusa (舞草), and Naminohira schools and other early Kyûshû smiths like Gunshô (軍勝), Sairen (西蓮), and Jitsu’a (実阿), or at very early Yamato blades (but also at later Shikkake [尻懸] smiths) and at Momokawa Nagayoshi (桃川長吉).
nashiji-hada (梨子地肌): A nashiji-hada is essentially a very fine and dense ko-mokume that is harmoniously covered with ji-nie all over. A “true” nashiji-hada is mostly seen at earlier Yamashiro schools like Sanjô (三条) and Awataguchi (粟田口) but sometimes the very finely forged jihada of certain Ôsaka-shintô masters like Tsuda Sukehiro (津田助広), Ozaki Suketaka (津田助広), Ikkanshi Tadatsuna (一竿子忠綱), and Shinkai (真改) is also referred to as nashiji or tending to nashiji, mostly when it is an edge case between super fine and uniform ko-itame and muji.
konuka-hada (粉糠肌・小糠肌): It is assumed that konuka-hada is a result of the Hizen smiths trying to emulate the nashiji-hada of the great Yamashiro masterpieces. As their approach turned out to bring forth quite a peculiar result, the terms konuka-hada or Hizen-hada (肥前肌) were coined to refer to these works. That means you should avoid using the term konuka-hada in any other context than Hizen as this just might cause confusion. Incidentally, this kind of hada reminds of rice bran (konuka), thus the name. Konuka-hada is hard to capture on pictures but you might be able to grasp the fineness and first of all the uniformity of the jigane of the 1st gen. Hizen Tadayoshi’s (忠吉) sunnobi-tantô that is shown below (which is by the way one of my most favourite blades, not mine though).
chirimen-hada (縮緬肌): Like at nashiji and konuka, we are facing with chirimen-hada the attempt to introduce school-specific differentiations of what is basically a very fine and uniform ko-mokume that is harmoniously covered with ji-nie all over. That means, nashiji, konuka, and chirimen-hada have basically the same technical background but they are not the same appearances (with just different names). A chirimen-hada is now the “result” that is seen on Aoe blades. It is named that way because the smooth and uniformly ji-nie covered special Aoe forging structure reminds of silk crepe (chirimen).
muji-hada (無地肌): The term muji-hada is used when a jihada is not discernible because it is so tightly forged, mostly in reference to shinshintô or gendaitô blades. The steel is not actually grainless but until more recent times it was very difficult to bring out such a jihada, even after careful polishing. However, details of blades described formerly as muji can now be brought out because of improved polishing techniques. And as muji-hada is actually an oxymoron, i.e. meaning about “no–structure/hada hada,” more and more the term muji-fû (無地風), lit. “tending to show no structure,” has become established to refer to the fact that the steel technically has a hada but which is just indistinguishable.
ha-hada (刃肌): Last but not least I want to introduce the term ha-hada which is used, as the name suggests, to refer to a forging structure that is very visible in the hardened part of the cutting edge, in short in the hamon. The picture below shows a Ko-Hôki blade, a school where you always can expect to see ha-hada. In this context it must be said that the course, border, and/or appearance of the hamon is actually influenced by the “underlying” forging structure. That means a smith just can’t apply any kind of hamon to any kind of jigane, or at least the result will be very difficult to foresee if these two elements are not going hand in hand. The intention behind and control of the smith in the interplay between steel and hardening is actually a highly sophisticated subject and an important factor when it comes to draw conclusions on his skill and (artistic) aim. As mentioned before, it takes a while to comprehend what is natural and unaffected, what is an excellent recreation of naturalness, what is a decent try to do so, and what is just incoherent. And for this you have to hold the blade in hands, that means it is impossible or next to impossible to draw such conclusions on the basis of a few pictures.
This was now an overview of the most common forging structures and I will point out characteristic features, peculiarities, and similarities later in the individual chapters on the schools. A third jigane part will follow soon that introduces the different forms of utsuri before we go over to the introductory chapter on hamon .