Important Juyo Ko-Hoki Sadatsuna
Overall length

86.1 cm

Blade length

67.2 cm

Blade thickness

Base 5.8 mm


Blade width

Base 30 mm

Tip 20 mm


2.25 cm

Tip (kissaki)

36 mm


593 grams




Ohara, Hoki province



Late 12th century

(Sadatsuna was active circa 1185 A.D.)


Japanese private collection

(A former Daimyo family, by repute)

Mr. Tsuruta, Aoi Art

German private collector

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Introduction, the Ko-Hōki school

Ko-Hōki school of Japanese sword makers is an ancient school from which many others have originated. Situated in Hōki province (伯耆国Hōki no kuni), known for its high-quality iron deposits.

"At any rate, Hōki (伯耆) has ranked number one throughout the country as a source of iron since olden times."

-Nihon to Koza, 1930s

Some of the iron is believed to have been exported to China, and with that, some knowledge about sword-making made it back by exchange and gave rise to the Ko-Hōki school. 

Its legendary founder was Yasutada, but since no works of him exist, Yasutsuna is widely regarded as the true founder of the school. He forged the Dojigiri or "Demon Cutter, one of the Tenka-Goken (天下五剣) or "Five [Greatest] Swords under Heaven" and possibly the most celebrated of them all.1 It was named so because legend has it that Minamoto no Yorimitsu slayed the demon Shuten-dōji with it.2

The Dojigiri by Yasutsuna
Tokyo National Museum accession number F-19931
National Treasure

The sword was initially dated to the 9th century, but more recent scholarship puts Yasutsuna's working period to around the 11th or 12th century. Yasutsuna's Dojigiri and Sanjō Munechika's Mikazuki ("Crescent Moon") are the two earliest curved Japanese swords in existence and the prototypes of what the world now knows as the "samurai sword."

"Yasutsuna, as we have seen, did more than anyone else to develop the Japanese sword as we know it, and his son Sanemori was almost his equal in renown. Their blades are among the finest and most typical examples of the earliest period, having a pronounced curve and taper, large itame grain, and hamon."

-B.W. Robinson, 1960

The Ko-Hōki school predates the dominance of the samurai class. They probably produced their swords mainly for the then-powerful Buddhist warrior monks, the Sōhei, who were the military dominant group at the time. Hōki was situated near the Daisenji (大山寺) temple of the Tendai Sect, situated high up on the Hoki Daisen mountain.

Throughout history, Ko-Hōki swords have inspired great swordsmiths. It were old Ko-Hōki swords, then already antique, that are said to have inspired some of Japan's greatest smiths, including Masamune, Norishige and Go Yoshihiro of the early Sōshū school.3 Much later still, around the late 17th century, the Dojigiri inspired the eccentric Ōmura Kaboku to recreate old Kotō works.4 His experimentation and the resulting book eventually inspired Suishinshi Masahide (水心子正秀) who developed himself as a grandmaster swordsmith, hailing in a revival of "golden age" Heian and Kamakura period styles of sword making in the late 18th century.5


1. Wikipedia article: Tenka-Goken. The Dojigiri is also featured in about any serious Japanese sword book. See Nobuo Nakahara; Facts and Fundamentals of Japanese Swords. Kodansha USA. 2017. Or Ogawa; Art of the Samurai: Japanese Arms and Armor, 1156–1868. Metropolitan Museum, 2009. Page 130. Also Kanzan Sato; The Japanese Sword. Japanese Arts Library. 1983. Page 90.
2. Markus Sesko; The Dojigiri-Yasutsuna.
3. Kotofanatic; The Ko-Hoki school.
3. Especially Norishige was clearly trying to emulate Sanemori's work, including some idiosyncratic marks on the tang. See Markus Sesko; Sorting out legends around Sanemori.
4. Thomas Helm; Mito Swordsmiths. 2010.
5. Markus Sesko; Swordsmiths of Japan. Lulu Publishing. 2014.


This example

A very well-preserved 12th-century tachi, representing one of the earliest forms of the Japanese curved sword. Ko-Hōki swords are full of extremes in tempering effects this sword is no exception. It has a bold mokume hada with choji hamon that would become the staple of Bizen swords for centuries to come. It also has the sunagashi, chikei and kinsuji that were raised to a high art form by the Sōshū school, emerging about a century after this sword was forged.

Besides the conspicuous, the sword also offers some very subtle effects to enjoy like utsuri, yubashiri and jifu.


Ko-Hoki Sadatsuna


(Plain English below)

Juyō Token, 33rd Juyō-shinsa of 1987; Mumei, Den Hōki Sadatsuna (伝伯耆貞綱)
(Designatd as an important sword by the 33rd important sword judging session of 1987. Unsigned, attributed to the tradition of Hōki Sadatsuna.

Sugata: shinogi-zukuri, iori-mune, relatively broad mihaba, deep sori, elongated chū-kissaki.
(Shape: standard shape with ridged spine, relatively wide blade, deep curvature and elongated tip section.)

Kitae: standing out itame mixed with mokume, ō-hada with ji-nie and chikei. Some jifu.
(Forging: a clear wood grain pattern with some burl grain, in large patterns. With martensite crystals above the temperline, some forming black gleaming lines in the steel. Some areas of dense martensite crystals that appear as black spots.)

Hamon: nie-emphasized gunome-chōji mixed with ko-midare, ashi and kinsuji. Also some yubashiri.
(Temperline: undulating pattern consisting of roundish elements, some resembling cloves, with some small waves. Some hardened "legs" in the temperline that run perpendicular to the edge, and black gleaming lines within the tempered zone. Also some isolated patches of tempered steel above the temperline.)

Bōshi: some notare-komi with a ko-maru-kaeri and nie.
(Temperline in tip: irregular, undulating line that turns back into the spine with a small, roundish turn.)

Horimono: both sides futasuji-hi, running into the nakago with kaki-nagashi.
(Carvings: two grooves on either side that run into the tang, some running off the tang.)

Nakago: ō-suriage, kurijiri, sujikai-yasurime three mekugi-ana, mumei.
(Tang: greatly shortened. Chestnut-shaped tang end. Slanting file strokes. Three peg holes. Unsigned.)

The blade is in remarkable condition for age, especially its thickness and the presence of a healthy, intact bōshi are a rarity on swords this old. Its steel surface has no areas that look tired or worn, and a vibrant, consistent hamon appears from base to tip.


33rd Juyō-shinsa, 1987; Den Hōki Sadatsuna

As mentioned, the sword was attributed to Den Hōki Sadatsuna (伝伯耆貞綱) by the N.B.T.H.K. Juyō-shinsa team of 1987. 

"Den" is usually used to describe a sword that exhibits most, but not all, typical traits of that smith. It does mean that the sword is thought to be of at least the quality of that smith and, in some cases, could even be better than what they are used to seeing from a particular smith. 

Ko-Hoki Juyo papers

Juyō papers of this sword. Issued 1987.


Juyo oshigata

Oshigata in the 1987 N.B.T.H.K. publication.

The Juyō jury's description:

"Following tradition Sadatsuna belonged to the School of  Hōki-Yasutsuna (安綱), only very few signed works from him remain. The signed blades we know show itame with ō-itame, chikei and ji-nie and a nie-emphasized hamon, based on ko-midare with supressed nioiguchi and very often kinsuji as well. At first glance one could confound them with contemporary Ko-Bizen-works, but the hada stands out more, the steel is more blackish and the hamon is more supressed, so different features can be seen. This blade shows the characteristics of the Ko Hōki School very clearly and within the group the interpretation speaks mostly for Sadatsuna. This means we see the traditional characteristics of this smith confirmed."


Tanobe Sensei sayagaki, 2012; Ko-Hōki Sadatsuna

Tanobe Michihiro is a former chairman of the N.B.T.H.K. and is considered by many to be the foremost expert on Japanese swords. His sayagaki (writings on scabbard) bring great added value, especially when it concerns unsigned blades that rely on expert attribution. Tanobe's sayagaki are found on some of the world's best Japanese swords and are highly valued for their profound insights.

Tanobe Sayagaki

This sayagaki reads:

Dai 33-kai jûyô-tôken shitei-hin

"Designated as an important sword at the 33rd Juyō session."


Hōki no Kuni Sadatsuna

"Hōki Province Sadatsuna"


ô-suriage mumei nari, dōkō issetsu ni Ōhara Sanemori no ko to tsutafu kuroaji o obite hada-tatsu ō-itame no hadaai to atsuku nie tsuku ko-midare ni kinsuji sunagashi no medatsu shizumu kagen to naru, yakiba ga dōha midokoro naredo dōkō ni wa toki ni hachû ni chōji no medatsu te ga keigan-saru honsaku wa kono yō na ten de shoden wa datō-narite jiba ni fukai aji-soi o kamosu yūhin nari.

"The blade is shortened and unsigned. Following a theory, Sadatsuna was the son of Ōhara Sanemori. The steel is blackish and the ō-itame-hada is standing out, and in combination with the rather suppressed yakiba in nie-emphazised ko-midare with remarkable kinsuji und sunagashi we can see the typical characteristics of the Ko Hōki School very clearly. With Sadatsuna one occasionally finds some chōji, like here, and so attribution to him within the school is most appropriate. A masterwork with an extremely tasteful jiba."


nagasa 2 shaku 2 sun 4 bu

"Blade length 2 shaku 2 sun 4 bu."
(Approx 67.9 cm)


shiki mizunoe-tatsu rôgetsu Tanzan Hendô shirusu + kaô

"Noted by Tanzan Hendō in the 12th month of the year of the dragon."
(A Pseudonym of Tanobe Michihiro. The year is 2012.)


The most important takeaway of the above is that Tanobe has no doubts and attributes it straight to Sadatsuna, without the den that gives some more leeway. Another interesting element is his closing sentence: A masterwork with an extremely tasteful jiba. This is extremely high praise from an expert who has seen it all.



This sword was published by Markus Sesko; Swords from the Nihonto-Club Germany 2. Lulu Publishing, 2013.


Ko-Hōki Sadatsuna

As mentioned, Sadatsuna is said to have been the son of Sanemori, who in turn is regarded as Yasutsuna's son. If both are true, that would make him the grandson of Yasutsuna. It is tantalizing to think how the maker of this sword may have been watching him hammer out the Dojigiri as a young boy. Of course, with smiths this far removed in time, it is very hard to know anything for sure.

Let us return to the bare facts we have on these three smiths. The works of Yasutsuna, Sanemori, and Sadatsuna are indeed close enough to one another to suspect at least master-student relationships between them. The gradual evolution in work style also seems to confirm this. Yasutsuna's date was traditionally given in the 9th century, but later scholarship put him around the time of Sanjo Munechika, who was active in the late 10th century. Some scholars believe there may have been more generations of Sanemori and Sadatsuna, which may help explain the gap between late 10th century and supposed grandson Sadatsuna's working period around 1185 A.D..

Another school of thought is that Yasutsuna lived much later, and the dates of Sadatsuna working around 1185 A.D. are accurate. That would place Yasutsuna's working period in the early 12th century and help explain why his works look so much more modern than Sanjo Munechika's. I am of this school of thought, which somewhat diminishes Yasutsuna's role as an innovator in sugata but leaves intact his brilliance as a bladesmith who created some of the most sophisticated swords of the earliest period in Japanese sword making.

Yasutsuna only signed his name, but Sanemori also signed "Sanemori of Ōhara in Hōki" which has lead researchers to place the entire school in Ohara. The school is thus also known as the Hōki Ohara school.

Sugata compared

Yasutsuna, Sanemori and Sadatsuna sugata compared, illustrated to scale.
Sanemori and Sadatsuna are closer together in overall shape.
In workmanshop, Sanemori and Yasutsuna are said to be very close.



Ko-Hōki swords are rarely found on the market, and when they appear, they often do so with serious condition issues due to their great age.

Presented here is a very important Ko-Hōki sword that besides the shortening that many old blades went through, survived in nearly perfect condition. It was probably well cared for from the moment it was made, well over 800 years ago, up until today with minimum polishes being done. It shows the sophistication of the school well, and was hailed as a masterpiece by Tanobe-san in the accompanying sayagaki.

The piece is attributed to Sadatsuna, who is believed to be directly related to the great Yasutsuna who forged one of Japan's most important swords.

Ko-Hoki Sadatsuna sword Juyo token
Ko-Hoki Sadatsuna sword Juyo token
Ko-Hoki Sadatsuna sword Juyo token
Ko-Hoki Sadatsuna sword Juyo token
Ko-Hoki Sadatsuna sword Juyo token
Ko-Hoki Sadatsuna sword Juyo token
Ko-Hoki Sadatsuna sword Juyo token
Ko-Hoki Sadatsuna sword Juyo token
Ko-Hoki Sadatsuna sword Juyo token
Ko-Hoki Sadatsuna sword Juyo token
Ko-Hoki Sadatsuna sword Juyo token
Ko-Hoki Sadatsuna sword Juyo token
Ko-Hoki Sadatsuna sword Juyo token
Ko-Hoki Sadatsuna sword Juyo token
Ko-Hoki Sadatsuna sword Juyo token
Ko-Hoki Sadatsuna sword Juyo token
Ko-Hoki Sadatsuna sword Juyo token
Important Ko-Hoki sword

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