This blade has a really powerful shape, starting with a width of 3.3 cm at the base and not tapering very much as it terminates with an O-kissaki....kind of archetype piece that makes Nanbokucho interesting is really nice to pick up. The masculine shape and o-kissaki cannot be beaten for the visual impression they give and kantei to this group is rather immediate on glancing at the blade.
The jihada is covered with ji nie which catch the light like a kaleidoscope as can be seen above, throwing back many colors to the eye. The body of the sword is filled with chikei. Of particular interest, chikei do not have to follow the folds of the steel as they are a separate matrix of material that is hardened within the body of softer steels. This we see in a very outstanding way in this blade as the jinie have combined to form small chikei which admirably speckle the whole surface. The hamon looks like a forest fire with peaks and valleys and sunagashi throughout it. Sometimes these older oshigata are not so accurate compared to what is made now. The artists who are making oshigata for the NBTHK currently are mind blowingly good and precise and it's common to see a blade like this with a lot of activity be more exciting than the oshigata, so it's something to keep in mind that an oshigata is a scan of a print of a drawing of an impression in someone's mind from what their eye saw.
This blade is made just like Soshu Hiromitsu in O-hada but the hamon construction is different. It's very healthy and intact, and this kind of masculine shape is what the NBTHK likes to see at Tokubetsu Juyo as can be seen by the reference item above. The reference blade in question is actually not as massive as this one. This blade is wider than the widest Kencho to pass Tokuju. The largest Chogi that on record is the meito Hachimonji Chogi and it has a motohaba of 3.2 cm which is smaller than this blade's 3.3 cm as well. There are only two Chogi at Tokuju that are this blade's equal for mihaba, one being only a half a millimeter wider. This is definitely a Tokubetsu Juyo candidate based on comparison to the reference pieces.
Kencho is believed to be the youngest brother of Chogi and Nagashige and they were sons of Osafune Mitsunaga.
Kencho is Chinese style pronounciation and transliterated as Osafune Kanenaga, and for the same reasons as Chogi. Maybe it is because the work of these two smiths is so different from standard Bizen work that we do this. Anyway, he is grouped with Chogi by his work style and generally it is a bit difficult to tell them apart.
We see that in the rankings as Kencho is Jo-saku, Chogi is Sai-jo saku, and Nagashige is Jo-jo saku by Fujishiro's determinations. But when we look at the work, Nagashige has a Kokuho and Chogi has none, while Kencho has 79 Juyo Token, 8 of which are Tokubetsu Juyo and another four Juyo Bijutsuhin. This is performance more in keeping with a Sai-jo saku smith. Chogi of course has a phenomenal record, with 81 blades passing Juyo, 28 of those went on to Tokubetsu Juyo and many Jubi and Juyo Bunkazai blades. However you look at these three smiths, the appreciation of the swords speaks very highly to their work. As well, they carry good reputations for cutting ability as Chogi is ranked Ryo-wazamono and Kencho is O-wazamono (higher than Chogi and just one step from the top rank of Sai-jo O-wazamono).
period Nanbokucho Koto (ca. 1360)
designation NBTHK Juyo Token
nakago o-suriage mumei
nakago nagasa 18.4cm