Yamashiro and Yamato Den
Excepting early SANJO school, Yamashiro sugata, like Yamato, is Toriizori.
Both exhibit wide shinogi ji. Yamashiro, however, does not have the raised shinogi ridges that are associated to Yamato. Yamashiro has comparatively identical thickness between shinogi planes. Thickness at the shinogi will be approximately the width of the mune.
Yamashiro hada is a fine ko-mokume. Both Yamato and Yamashiro steel is finely worked. Both have the reputation of being Nash ( fine grained like pear flesh). Unlike Yamashiro, Yamato shows Masame mixed with mokume. The fineness of YAMASHIRO steel will show a particular "moisture" or wet appearance known as Kyoto steel.
Yamashiro will show less nie inside the Yakiba. Nie is hard steel that differentiates from soft at the quench. Nie, and the many forms of crystalline steel, were created by tightly bound carbon resulting from the forging process of the individual smiths. The hardness developed in the extra-folded Yamashiro tradition disallows soft steel to form in the yakiba. Nie in Yamashiro blades, therefore, is to be found along the line of hamon or as ji nie, and less in the yakiba.
Yamashiro, as with early Yamato, will mostly have little or no turnback (yakizume). Maru and kaen are typical. Strong nie is not unexpected.
The nakago is usually long and gently curved. There are a few Kijimonogata (pheasant leg shaped) in the early works. Kurijiri (chestnut shaped end to the tang) is found on early pieces exclusively with more variety in the later period (post Kamakura). Signatures are usually short.
The most important feature that distinguishes Yamato fromYamashiro is the raised shinogi and mune ridge lines. Both provinces used toriizori and have wide shongi ji, but the raised shinogiand mune of Yamato blades will differ markedly. (Note: Raised shinogi can also be found on Bitchu blades, Satsuma, Suwa,2nd Bizen Kanemitsu, and the Mino lines if Kanemoto and Kanesada, most of which have some influence from Yamato den schools).
The hada differs as well. Yamato blades exhibit masame or an itame/masame mix (Yamashiro used ko-mokume almost exclusively).Reminder: Masame "straight grain" can appear in a mix but was also often used as the structural basis of a laminate. Masame along the ha or the shinogi may be the sword’s structural plan view. Yamato used ko-mokume or itame, but masame at play shows a basic structural distinction from Yamashiro. Both Yamato and Yamashiro can have the well-worked hada that reminds of nashiji.
Early swords are in suguha, sugu komidare or komidare ha in nie. Some have ashi. Yakiba of later blades may be wider. O-midareGunme/komidare mixes are seen with, perhaps, less pronounced nie.
NIe and some Kaen (flame). Most are without turnback (yakizume). Later boshi might be midare (some are in full temper (ichimai) in Kanabo school).
Yamato nakago is much like that of Yamashiro. They have length and gentle curve. A few of the older pieces are kijimonogata. Famous yasuri (file marks) for Yamato is Takanoha (falcon feather pattern) and Higake (diagonal cross hatching)
Prior to the Nambokucho period, only three of the Gokaden existed: Yamashiro, Yamato, and Bizen. All three probably had their roots in the Nara period. Prior to the Nara period, swords in Japan had the straight, double-edged shape of swords from the continent (referred to by many names including ken and tsurugi) and steel forging was undoubtedly introduced to Japan from China through the Korean peninsula. The first major change in shape is realized in the National Treasure Sword Kogarasu Maru, which has a central shinogi, deep curvature, and the back edge is tempered down about a third of the blade. The semi-legendary maker of the Kogarasu Maru was a Yamato smith named Amakuni working in the 8th century. No authenticated signed works have been found, but there are several works of similar shape and style from the 8th and 9th centuries.
One of the oldest bodies of signed work is by the Yamashiro den Sanjo Munechika and his Sanjo school. Munechikas work dates from 987 through the first half of the 11th century.
Yamashiro schools Yamato schools
Sanjo mon Early
Gojo mon Nara school: Amakuni
Awataguchi mon Senjuin
Ayanokoji mon Ryomonji
Rai mon Taima
Ryokai Ichirui Shikkake
Hasebe Ichirui Later
Historical periods in Japan of interest to students of the sword
The technical descriptions for both Yamashiro and Yamato den are taken directly from Robert Cole’s excellent reference web page http://www.sho-shin.com/. It includes excellent photos and oshigata of reference blades, detailed lineages of the various schools, maps, and more information than you can absorb in any single sitting. I highly recommend it.
Also highly recommended is Markus Sesko’s site, https://markussesko.com. He is an excellent translator of original texts, and the author of no few compilations of his own. Well worth the time.
The other main reference is Harry Watson’s translation of the Nihonto Koza, Volume 1, which includes massive amounts of information about schools, lineages, and famous swords.
Remember SEPT, our mnemonic for looking at a blade
Shape (sugata): the overall shape and proportions of the blade including type (tanto, tachi, katana). Ubu (original) or sugiage (cut down at the tang) Shinogi zukuri or hira zukuri (flat surface lacking a shinogi ridge), the amount, if any, of the taper from base to tip, and the shape and proportions of the tip. Sugata tells you when the blade was made.
Edge: the pattern of the hamon and the crystalline forms found in and around the hamon, the hataraki. The hamon points to the school and maker of the blade.
Pattern: the kitae, the forging patterns of the steel and the texture and relative hardness of the steel as well as any crystal patterns visible in the jihada, the steel itself. In the koto period (pre-1600) all sword steel was smelted locally. The Japanese speak of the flavor of the steel. The steel tells you where the blade was made.
Tang (nakago): The shape of the tang points to the school. The file marks on the tang (yasuri mei) also point to the school and smith. The color of the patina points to both the age of the blade and the origins of the steel. And last, the signature, date, or any other markings on the tang can indicate the smith or school (Shin mei, a true signature. Gimei, a false or forged signature).
SEPT is a handy acronym, but the actual order of looking at a blade should be SPET. Most sword references describe blades in that order and that is how you should first view a blade. Shape tells you when, kitae, or the patterns in the steel and forging tell you where, the hamon tells you who, and the tang should confirm the previous data. If it doesn’t, believe the data, not the tang.