Rai Kunimitsu KatanaRai Kunimitsu

periodLate Kamakura / Early Nanbokucho
designationNBTHK Juyo Token
nakago16.1 cm, O-suriage, mumei, two mekugiana
nagasa70.7 cm
sori1.2 cm
motohaba2.9 cm
sakihaba2.0 cm
kissaki nagasa3.5 cm
nakago sorinone

The golden age of swords in Japan is commonly considered to be the Kamakura period. During this time there were many great smiths in the schools of Yamato, Bizen and Yamashiro and as the period began to wane the rise of the Soshu den was no exception.

There was a moment during the Kamakura when the three greatest makers of tanto to have lived were working in their prime. They are Shintogo Kunimitsu in Kamakura, Yoshimitsu in Awataguchi, and Rai Kunitoshi in Kyoto.

The Rai school was founded in legend by a smith named Kuniyoshi, who is considered to have come from Korea. The character Rai means "come", and the implication is that this relates to the founder coming from overseas to Japan. There are no extant works by Rai Kuniyoshi though, so in practical terms the founder of Rai is considered to be Rai Kuniyuki. His style is purely mid Kamakura, making majestic broad blades with dense choji hamon.

The son of Rai Kuniyuki is the smith referred to as Niji Kunitoshi (i.e. "two-character Kunitoshi"). Signed work by this smith is generally in the style of his father, utilizing choji in the hamon and with the wide blade and ikubi kissaki of the times. There is some confusion because following Niji Kunitoshi is the smith referred to as Rai Kunitoshi. The work of Rai Kunitoshi in contrast is more elegant and less flamboyant, often featuring suguba and a tapering sugata. When his signature is found, it takes the form of three characters reading 来國俊 (Rai Kunitoshi). He can alternately be called Sanji Kunitoshi (three character Kunitoshi).

The confusion I speak about is in regards to whether or not these two smiths are one and the same. There are several theories, one is that Rai Kunitoshi is the son of Niji Kunitoshi. Another states that Rai Kunitoshi is the younger brother. The theory that would seem to be gaining ground is that they are the same smith, and the change in signature style coincides with a style change in the work.

Luckily for us, there is a dated work of 1315 by Rai Kunitoshi where he placed his age of 75 years on the nakago. Homma sensei, the founder of the NBTHK and renowned expert on Nihonto, wrote this about Rai Kunitoshi in Great Masterpieces of Japanese Art Swords:

[In regards to the dated work at 75 years of age] ... Together with the date inscription, this is an important reference material for the study of Rai works. Of those signed works by Rai Kunitoshi which have been examined to date, the earliest is dated Sho-o 3-nen (at the age of fifty), and [the latest is] Genkyo Gan-nen (at the age of eighty-one).

Fifty years of age would seem to be unusually late for a smith of grandmaster skill to appear on the scene. There is dated work by Niji Kunitoshi, a famous one with the date of 1278, and one with the date of 1286. There is no other dated work by Niji Kunitoshi that I am aware of, and if we are to believe that these works are by Rai Kunitoshi at the beginning of his career then this would make him 38 and 46 years old at their time of production, which would allow him decades of experience to accumulate the skill he displays under the old signature style.

Rai Kunimitsu

Rai Kunimitsu is one of the group of very famous smiths with Sai-jo rankings from Fujishiro. He is considered to be the son of Rai Kunitoshi with the given name Jirobei, and inherits the main line of Rai through his father. He begins independently signing his own work in the late Kamakura period and works into the Nanbokucho. Fujishiro indicates that his dated work shows a 36 year working period starting in Showa (1312), but it's possible this has been extended with finds that post-date his writings. Yamanaka has him starting earlier in Kagen (1303).

Rai Kunitoshi and Rai Kunimitsu were famous and successful in their own time. Furthermore they have been given as gifts to and from the Shogun in the Edo period, indicating that this esteem has carried through the ages. Quoting from Fujishiro:

It is not hard to imagine why the kaji Kunitoshi, Kunimitsu, and father and son Kunitsugu were famous and prospered in their time. Among the names of the swordsmiths that have been handed down to the present day, there are two cases, the one in which their fame was circulated about while they were still living, and those which became famous after they died. It is probably reasonable to consider Kunitoshi nado among the former.

Some experts have declared Rai Kunimitsu to be the top smith of the entire Rai school, though mostly he is seen as a little bit junior to Rai Kunitoshi who is the pre-eminent smith of Rai in my opinion. His work is seen both with choji similar to his father's early style, and the later style of Rai work with suguba. As a smith he made several different styles of tachi staying current with the times, and four of five different styles of tanto, from typically Kamakura through to sunnobi style from the Nanbokucho. Sometimes a bit of Soshu style can be seen in his work, though not as much as in Kunitsugu. Today there are many works of his that are held at the highest levels of appreciation: Kokuho (National Treasure), Juyo Bunkazai and Juyo Bijutsuhin, and Tokubetsu Juyo Token.

Of interesting note he on occasion signed "Rai Minamoto Kunimitsu" and the Minamoto is something also seen rarely on Rai Kunitoshi. Rai works are known to have somewhat thin skin and after some polishing some rough texture often appears which is known as "Rai Hada" and is generally not considered a flaw, though it is of course more desirable to have a piece that does not show this feature.

Numerous Rai smiths would follow Rai Kunimitsu: Kunizane, Tomokuni, Mitsugane, Kunitsugu, Kuniyasu, Kuninaga, Kunihide, Yukimune, Yoshimune, Mitsusada, Yukihide, Kunifusa and their various descendants.

Juyo Token Rai Kunimitsu Katana

Juyo Token Rai Kunimitsu Katana

This is a gorgeous work showing off the skill of Rai Kunimitsu very well. In form, it has the elegance of his father plus the touch of robustness expected from Rai Kunimitsu's work. The hamon shows small ashi which recall the earlier work of Niji Kunitoshi and the nie are very bright and strong.

The forging is the very pleasing and well crafted ko-itame that gave the Rai school its high reputation, silky though there is a small bit of Rai hada on one side. The bo-hi ends in the middle of the nakago indicating that not so much was cut off this sword, its likely that the signature was just below the cut mark. Sadly this is a fairly frequent occurence and zaimei Rai works are very rare.

It is an excellent example of late Kamakura Yamashiro technique, and of the Rai school which was ascendant at this time. The NBTHK notes him as a smith of the very beginning of Nanbokucho, but Fujishiro places him earlier in Showa. Given that Rai Kunitoshi was 75 in Showa 4, it's most likely that Rai Kunimitsu was already active at this point. I've placed the blade as late Kamakura / early Nanbokucho accordingly.

An interesting artifact can be seen on the blade that is not noted by the NBTHK. There is the remains of a kinpunmei (attribution written in gold lacquer). It's not clear if it was removed intentionally or is worn away. It's a three character signature which does indeed appear to read "Rai Kunimitsu." There have been cases in the past where these are removed before shinsa and then the sword ends up attributed to the same smith as was on the lacquer or kinzogan attribution. The rationale for this is a little bit hard to understand.

Rai Kunimitsu Katana Oshigata

Juyo Token Katana

Appointed on the 10th of July, 1976, 24th session.

Katana, Mumei, Den Rai Kunimitsu


Tight ko-itame mixed with some masame close to the ha. There are also ji-nie.


Suguba with lots of small ashi. There is a hint of kuichigai on the omote side and quite a bit of ko-nie.


Sugu and ko-maru.


On both the omote and ura there is bo-hi that runs down to the middle of the nakago and ends in maru-dome.


O-suriage with a kiri jiri. Kiri file marks with 2 megkuiana. Mumei.


It has been reported that Rai Kunimitsu was either a son or a student of Rai Kunitoshi. Kunimitsu worked from the Karyaku era (A.D. 1326 - 1329) [late Kamakura] through the Jowa and Kano (A.D. 1345 - 1352) years of the Nambokucho period. Among the Rai school smiths, Kunimitsu is recognized as one who made the widest variety of blade styles, which include traditional suguha, suguha mixed with small gunome and large midare.

This particular katana blade is a work of suguha with lots of small ashi. Though the blade is an O-suriage mu-mei, its attribution to Rai Kunimitsu is very well supported.

Rai Kunimitsu Katana Sayagaki

Tanobe Sensei Sayagaki

  1. 第廿四回重要刀剣指定品。
    Dai 24-kai jūyō-tōken shitei-hin.
    Designated jūyō-tōken at the 24th jūyō-shinsa.
  2. 城刕来国光。
    Jōshū Rai Kunimitsu.
  3. 大磨上無銘ト雖モ地刃ニ同工ノ特色ヲ明示シ出来宜敷ク格調頗ル高矣。
    ō-suriage mumei to iedomo jiba ni dōkō no tokushoku o meiji-shi deki yoroshiku kakuchō sukoburu takai
    The blade is ō-suriage mumei but the jiba shows the characteristic features of the smith and the deki is highly dignified
  4. 珍々重々。
    It is very rare, and very precious.
  5. 長貳尺参寸三分弱有之。
    nagasa 2 shaku 3 sun 3 bu-jaku aru kore.
    length 70.7 cm.
  6. 峕季癸巳暦菊月探山邉道識。
    toki mizunoto-hebidoshi kikuzuki Tanzan Hendō shiki + kaō.
    Judged by Tanzan Hendō in the ninth month of the year of the snake of this era (2013).