Among the swords of the celebrated Ko-Bizen school, those of the founder Tomonari are remarkable. Differing in some detail from the swords of the other great Ko-Bizen master Masatsune, they tend to be subtle, tightly packed with prominent grain, of elegant form and with a dark hue to the steel.
The well used fighting tachi were of kuro-urushi (black lacquer) type. Not only were they practical, they were easy to manufacture and popular among senior warriors. The tsuka were usually wrapped with lacquered rattan.
The blade was mounted with the present koshirae some five hundred years ago in the Muromachi period and is similar to that used by the Minamoto warrior, Nasu no Yoichi Munetaka; the renowned archer who gained fame at the battle of Yashima. The story goes that when the Taira were driven from Kyoto in 1182, the Emperor Antoku, together with the Empress Nii no Ama and their children retreated to the shrine at Itsukushima in the Inland Sea. There, they retrieved a legendary pink fan bearing the hino maru (sic.) [rising sun] which caused arrows to rebound upon the enemy. The fan was mounted at the mast-head of a royal barge as a challenge to the Minamoto. Nasu no Yoichi, galloping into the waves, released his arrow and struck the central rivet, which held the leaves together, thus shattering the fan. See Heike Monogatari.
It is not difficult to imagine why the Satake owner, with his family roots inextricably interwined with those of the Minamoto clan, would want to reproduce the hero's Heian tachi mount to complete his Heian blade.
The actual sword used by Nasu no Yoichi in the famous battle still exists, having been handed down through the Nasu family at least until Showa 10th year (1935) when it was registered as an important cultural property (see Shuko jusshu no. 372 for illustration). Combat technique over the years has resulted in some minor modifications. The exaggerated arc to the hilt of the original, for example, has been changed to a gentle curve, presumably as a result of developments in the art of Iai, sword-drawing.
It is interesting to note that both the Satake family, who owned this tachi and the Nasu family used the same fan motif for their family crest, the Nasu family, having added the character ichi [one] probably from the name.
The Satake family can be traced back to Minamoto Yoshimitsu in the Heian period.
Yoshimitsu, so called Shinra no Saburo from the temple of Shinra Myohojin, was the brother of Yoshiie, a distinguished musician; famed for his knowledge of archery and horsemanship who originated the Ogasawara school of court etiquette.
Yoshinari (circa 1090), son of Yoshimitsu, was the first to use the name Satake, and he was followed by:
Hideyoshi (1151-1228), great-grandson of Yoshinari, inherited the domain of Satake in Hitachi. When Yoritomo attacked the Taira, he refused to follow, and secured himself in his stronghold at Kanasa.
Yoshinori (1395-1462), descendant of Hideyoshi, supported the kanryo of Kamakura Ashikaga Mochiuji, against the Uesugi in 1416. After the death of Mochiuji in 1439 the Kanto region was divided among 7 families the head of which were the Satake daimyo.
Yoshiaki (no dates), defeated a union of neighbouring daimyo in 1569, greatly enlarging his holdings at their expense.
Yoshishige (1547-1612), took the field against Ashina Moriuji, subsequently, Soma Moritane and Ishikawa Akimitsu re-established Ujimasa who attacked Yoshishige. Nevertheless, Yoshishige became the master of Hitachi and Yoshinobu inherited his immense domains in 1590.
Yoshinobu (1570-1633), co-operated in the endeavours of Hideyoshi against the Joho of Odawara and later participated in the government of Hitachi province. Afterwards he was installed at Mito, with an income of 800,000 goku.
The descendants by order of the Shogunate remained in Hitachi until the restoration period, after which they were transferred to Akita (Dewa) with an income of 205,000 goku. Since then they have variously received the titles of Baron, Marquis and Viscount.
The Satake family possibly transferred ownership of the sword to the Oshima family, a samurai family from Akita traditionally in the service of the Satake, in the late Meiji period (circa 1907)
The Oshima family register records Viscount Oshima Hisanao who lead an armed force in the Seinan engagement during the Satsuma rebellion (1877). He lead his troops against the Chinese in Manchuria in 1885, and fought a bloody campaign against the Russians in 1907. It was perhaps for these gallant exploits that he received the Tomonari tachi, which has been handed down by descent to Oshima Tadashi. He is also recorded as being a prominent collector of swords and accoutrement, owning among other things the famous Kaneie tsuba registered as an important art object.
Attached to the koshirae, a small owner's tag states; kuro urushi karasu-do so-tachi, mumei, (black lacquer dark copper so-tachi, unsigned) belonging to Viscount Oshima Tadashi. It also states the koshirae is similar to that of Nasu no Yoichi.
The question often posed by scholars and collectors, "why are such masterpieces not signed". The answer may lie in the authorities penchant for acquiring valuable swords. Important swords in those days had a value far in excess of land or aristocratic wealth. This encouraged the nobility to go "sword hunting" and one of the obvious targets would be the eighty-six or so tozama daimyo and senior samurai who owned many swords. It would have been prudent for the owners to remove the signature, thus reducing the desirability to one of Toyotomi Hideyoshi's or the Tokugawa Shogun's visiting officers. The Satake, who were rather less than precise, about whose side they were on at the great battle of Sekigahara, were nevertheless, classified as tozama daimyo (against the Shogun). Still, they were one of the more senior daimyo and were known - like many others - to have owned many important swords without signatures.