Ikkanshi Tadatsuna (一竿子忠綱)
Ikkanshi Tadatsuna was a sword craftsman in the Settsu Province who lived in the Genroku era during the Edo period. He was the second Omi no kami (Governor of Omi Province) Tadatsuna. His swords were categorized into Shinto (new sword), Jojosaku (the second rank) (上々作) and Yokiwazamono (the third grade of sharpness). His surname was the Asai clan (浅井) and his common name was said to be 'Mandayu' (万太夫) (There is no sword with an inscription of Mandayu). The word 'Ikkanshi' refer to the go (byname) and was used for the swords with the curving of blade as inscription which were produced around the Kanei and Genroku eras.
His father Tadatsuna identified himself as a descendant of Kunitsuna AWATAGUCHI who was a sword craftsman in Kyoto in the Kamakura period and moved to Osaka. The first Tadatsuna was assigned to Omi no kami (the governor of Omi Province). Nagatsuna was his disciple. The second Tadatsuna was assigned to Omi no kami as well as his father.
Therefore, both father and son carved the inscription of 'AWATAGUCHI Omi no kami Tadatsuna.'
Some inscriptions of the first Tadatsuna's work in his later years are similar to those of the second Tadatsuna's, so that it is thought that those were made by both of them. The major difference of the inscriptions between the first and the second was a letter of 'Tsuna;' the angle of 'itohen' (a part of kanji) which was gadded was different.
At first, the second Tadatsuna produced Ashinagachoji (a name of a sword) (足長丁子) which style resembled that of the first. Around the Genroku era, he began to produce Toran midare (a temper pattern) (涛瀾乱れ) influenced by Tsuda Echizen no kami (the governor of the Echizen Province) Sukehiro and Suguha (a temper pattern)(直刃) with nie (grainy martensite) and nioi (fine-grained martensite) like the style of Shinkai INOUE, and finally started carving by himself. Many works have a dense carving on the body of blade which reminds the prosperity of Genroku era such as Umekurikara (梅倶利伽羅) and Koi no Takinobori (A carp swimming up a fall) other than old Kenmakiryu (剣巻龍). The inscriptions of the sword with carving are usually put on nagomi (a part of the blade in hilt) as 'hori dousaku' (彫同作) or 'horimono dousaku' (彫物同作).
The characteristics of style
Tsukurikomi (cross-section form)
Most of them are short sword and long sword of about 63 cm long. They have a round shape with funbari (a kind of folding-fan shapes) and sakizori (warpage around the top), compared to Kanbun New Swords in the previous period. Most of their tips have sharp shape.
Jigane (a body of iron blade)
Jigane was fine-grained and developed into a bright Osaka new sword. It is Slash-cut pattern with mokume (wood grain) pattern. The pattern of Shinogiji (a part of Mune-side [the other side of blade]) is grain with parallel growth rings.
Hamon (temper pattern of a sword blade)
It is basically Osaka yakidashi (a temper pattern around the root of blade) which is added with Gonome (regular wavelike pattern) of a broad regular width which could reach the line of ridge. At the beginning, he produced Ashinagachoji (a name of Hamon) and in the prime of life he produced the swords of Suguha and Toran midare mixed with Ashinagachoji. The width of blade of the sword with carving is narrow. The blade has grainy martensite without any patch and Sunagashi (a pattern of martensite). When Ashinagachoji is burned and produced, it shows long pattern and Nioiashi (a pattern with small grains) ahead of Nieashi (a pattern with large grains) seems to go through the tip of blade. Because of the effect of Sunagashi around the top of Ashinagachoji, it looks like having a bulge like a balloon. The Hamon of Boshi (a tip of a sword) is Komaru, which shows small turning angle.
Nakago (a part to hold a sword)
The shape of the tip of nakago is narrow and Katayamagata, Haagarikurishiri. It has a diagonal yasurime (a pattern of hilt) with kesho yasuri (designed yasuri). Finishing Muneji (the other side of a blade) of Nagomi, a thick part of a sharp angle is slightly shaven and rounded off to make full to the touch.
There is a dense carving on blade as mentioned above.
There is a sword which is designated to an important cultural property (the sword with the inscription 'Ikkanshi Tadatsuna hori dosaku, on a lucky day September, 1709,' held at the Kyoto National Museum). In addition, many works are designated to a cultural property by prefectural governments and municipal governments.
It is said that Zenzaemon SANO killed wakadoshiyori (a managerial position in Edo bakufu) Okitomo TANUMA, a son of roju (senior councilor) Okitsugu TANUMA, at the Edo Castle on May 13, 1784 with a short sword of the second Tadatsuna. Since Sano fought back Okitsugu TANUMA who had such a great power as being called Tanuma period (the period when Okitsugu Tanuma led the government for about 20 years during the middle of the Edo period) and was famous for bribery, he was admired as 'Yonaoshi Daimyo-jin' (the Great God who reformed the world). In addition, the sword of the second Tadatsuna which was his sashiryo (sword) became popular.