One-sword style

It is one of the major schools of early modern swordsmanship, and its founder was Ito Ittosai Kagehisa. Ittosai traveled around the country as a martial artist throughout his life, and it is unclear where he died, but among his disciples, two outstanding names stood out: Kotoda Kageyuzaemon Toshinao (the founder of the Kotoda school) and Mikogami Tenzen Yoshiaki (the founder of the Ono school). Among them, Norizumi was the direct descendant of Ittōsai, and was summoned by Tokugawa Ieyasu with a stipend of 200 koku during the Battle of Sekigahara in 1600 (Keichō 5). He later served as the swordsmanship instructor to the second shogun, Hidetada, and changed his name to Ono Jirōemon Tadaaki (1547-1624). He was bestowed with a stipend of 600 koku and became famous in the school. Tadaaki's eldest son, Tadakata, died young, but his second son, Tadaya (according to one theory, Tadaaki's younger brother), succeeded Ittosai and called himself Ito Norizen (the founder of the Tadaya school), and his third son, Sukekuro (according to one theory, the legitimate son), became the second head of the Ono family and called himself Jiroemon Tadatsune (1608-1665), served the third shogun, Iemitsu, as a shoinban (a shoinban), and was granted an additional 200 koku of rice, giving him a total of 800 koku of rice. Tadakata's son, Magobei Tadakazu (1604-1672), (according to one theory, the son of Tadaaki's older sister), received a license from Tadaaki at the age of 23 in 1626 (Kan'ei 3), and served the Mito family, becoming the founder of the Mito school.

Furthermore, Tadaaki's school produced many talented martial artists, including Obata Kanbei Kagenori (founder of the Mikogami school) of Koshu-ryu military science, Tadaya's school produced Kamei Heiemon Tadao (later adopted by Tadaya and changing his surname to Ito), Tadao's younger brother Negoro Hachikuro Shigeaki (founder of the Tenshin Dokumyo-ryu school), Mamiya Gorobei Hisanari (founder of the Mamiya school), Mizoguchi Shingozaemon Masakatsu (Hanzaemon Shigenaga, founder of the Mizoguchi school), and Tadatsune's school produced Kaji Shinuemon Masanao (founder of the Kaji school). These created the foundations for what would eventually become a major school. Tadatsune's son, the third Tadao (1640-1712), was praised for his exquisite technique, perfected the Kumitachi style of sword fighting that had been practiced since Ittōsai, and spread his influence among feudal lords, including the Tsugaru Ecchu no Kami. However, Tadao had no sons, so he adopted Naiki, the second son of the Shoinban Okabe Tadatoyo, as his son-in-law. The fourth Tadaichi (1659-1738) advanced from the Okosho group to the Osakite gun commander and Mochiyu-gashira, and it is said that because of this, the family profession of swordsmanship became secondary.

Nakanishi Tane Sada, a senior disciple of Tadakazu (the founder of the Nakanishi school), received a license to teach in 1748 (Kan'en 1) and opened a local dojo in Shitaya-Neribeikoji, Edo, where he worked hard to promote the Itto-ryu style, but his son Tanetake, during the Horeki era (1751-1764), developed protective gear such as masks, gauntlets, and bamboo do, and began practicing striking with a bamboo sword. This bamboo sword striking quickly became popular, and new students came in one after another.

In response to this, in 1787 (Tenmei 7), the head of the Ono school, Sōke, warned that shinai-uchi was merely a supplement to the training in kumitachi, and that it was against the school's style to focus solely on shinai-uchi. He continued to ask for it to be discontinued after that, but the students at the time could not bear the old training method of stacking kiri-gumi swords one by one, and in 1796 (Kansei 8), the sixth head of the school, Tadayoshi, was forced to halve the 50 omote-kirigumi odachi swords to 25, and instead added seven ko-nai and seven tōbōjutsu swords.

This Nakanishi school produced many famous swordsmen who were active at the end of the Edo period and during the Meiji Restoration, including Asari Matashichirō, Terada Muneari, Shirai Toru, Takayanagi Matashirō, Takano Mitsumasa (grandfather of Takano Sasaburo), Chiba Shūsaku, who founded the Hokushin Ittō-ryū school, and Yamaoka Tesshū, who was later bestowed with the secret teachings of the orthodox Itto-ryū style by the ninth master Ono Nario and advocated the Itto Seiden Mutō-ryū style.

The Itto-ryu (Ono-ha) school of swordsmanship was compiled in four volumes: "The Twelve Articles of Itto-ryu Heist (Shoten)", "The Provisional Handbook of Itto-ryu Heist (Middle Transmission)", "The Itto-ryu Heist Catalog (Main Catalog)", and "The Itto-ryu Division Catalog". After receiving all of these, it was required several to ten years after the student had mastered the fundamentals of swordsmanship before he was given a license to teach swordsmanship.

[Ichiro Watanabe]

"Complete Collection of Japanese Martial Arts, Volume 2" (1966, Jinbutsu Oraisha)" ▽ "Secrets of Itto-ryu by Junzo Sasamori (1965, Dosho Kankokai)" ▽ "The Encyclopedia of Japanese Martial Arts, Volume 2" (1982, Dohosha Publishing)

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

近世剣術の主要流派の一つで、伊藤一刀斎景久(いとういっとうさいかげひさ)を流祖とする。一刀斎は生涯一兵法者として諸国を歴遊し、その終焉(しゅうえん)の地もさだかではないが、その門弟では古藤田勘解由左衛門俊直(ことうだかげゆざえもんとしなお)（古藤田派の祖）と神子上典膳吉明(みこがみてんぜんよしあき)（小野派の祖）の両名が傑出している。なかでも典膳は一刀斎の嫡伝を受け、1600年（慶長5）関ヶ原の戦いのとき、200石をもって徳川家康に召し出され、のちに2代将軍秀忠(ひでただ)の剣術師範を勤め、小野次郎右衛門忠明(おのじろうえもんただあき)（1547―1624）と改名、600石を拝領して流名をあげた。忠明の長子忠方は早逝したが、二男忠也（一説に忠明の弟）は一刀斎の跡目を継いで伊藤典膳（忠也派の祖）を称し、三男助九郎（一説に嫡子）は小野家2代となって次郎右衛門忠常（1608―1665）と称し、3代将軍家光(いえみつ)につかえ、御書院番を勤め、200石を加増されて、800石を知行した。また忠方の子（一説に忠明の姉の子）孫兵衛忠一（1604―1672）は1626年（寛永3）23歳で忠明より免許を得、水戸家に仕えて水戸派の祖となった。

　さらに忠明の門には、甲州流兵学の小幡勘兵衛景憲(おばたかんべえかげのり)（神子上派の祖）、忠也の門には亀井平右衛門忠雄（のち忠也の養子、井藤姓に改める）、忠雄の弟根来八九郎重明(ねごろはちくろうしげあき)（天心独名流(てんしんどくみょうりゅう)の祖）、間宮五郎兵衛久也(ひさなり)（間宮派の祖）、溝口新五左衛門正勝（半左衛門重長、溝口派の祖）、ついで忠常の門からは梶新右衛門正直(かじしんえもんまさなお)（梶派の祖）など、数多くの俊才を輩出し、やがて一大流派を形成する基盤をつくった。忠常の子3代忠於(ただお)（1640―1712）は技術の精妙をうたわれ、一刀斎以来の組太刀(くみたち)を大成し、津軽越中守(えっちゅうのかみ)をはじめ諸侯の間にも勢力を広めた。しかし、この忠於には男子がなく、御書院番岡部忠豊の次男内記(ないき)を婿養子に迎えたが、この4代忠一(ただかず)（1659―1738）は御小姓組(おこしょうぐみ)から御先手(おさきて)鉄炮頭(てっぽうがしら)、持弓頭(もちゆみがしら)へと進み、このために家職の剣術は二の次になったといわれる。

　忠一の高弟、中西忠太子定(たねさだ)（中西派の祖）は1748年（寛延1）指南免許を受けて江戸・下谷練塀小路(したやねりべいこうじ)に町道場を開き、一刀流の鼓吹に努めたが、その子忠蔵子武(たねたけ)は宝暦(ほうれき)年間（1751～1764）に至り、面、籠手(こて)、竹胴などの防具をくふう整備し、竹刀(しない)打込み稽古(げいこ)を始めた。この竹刀打ちはたちまち人々の人気を集め、入門者が相次いだ。

　これに対し、1787年（天明7）小野宗家(そうけ)は、竹刀打ちはあくまで組太刀修業の補助であり、竹刀打ち一色にすることは流儀に反することを警告し、その後もしばしば中止するように求めたが、当時の門人たちは昔のような切組(きりぐみ)を1本1本積み重ねていくという修練方式に耐えられず、1796年（寛政8）宗家の6代忠喜(ただよし)も、やむなく表切組大太刀(おもてきりぐみおおだち)50本を25本に半減し、かわって小(こ)しない7本、刀棒術7本を加えて指南するというありさまであった。

　この中西派からは、浅利又七郎(あさりまたしちろう)、寺田宗有(てらだむねあり)、白井亨(しらいとおる)、高柳又四郎(たかやなぎまたしろう)、高野苗正(たかのみつまさ)（高野佐三郎の祖父）や、北辰一刀流(ほくしんいっとうりゅう)を創始した千葉周作、のちに9代小野業雄(なりお)から正統の秘奥を授与されて一刀正伝無刀流を標榜(ひょうぼう)した山岡鉄舟など、幕末・維新期に活躍した名剣士を多数輩出した。

　なお一刀流（小野派）の伝書は、『一刀流兵法十二ヶ条（初伝）』『一刀流兵法仮字書（中伝）』『一刀流兵法目録（本目録）』『一刀流割目録』の4巻で、これらをすべて授与されたのち数年ないし10年、剣術の通根を見了して、初めて指南免許状が渡されたのである。

［渡邉一郎］

『『日本武道全集　第2巻』（1966・人物往来社）』▽『笹森順造著『一刀流極意』（1965・同書刊行会）』▽『『日本武道大系　第2巻』（1982・同朋舎出版）』

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