Ken-tai Ichi no Kata

Ken-tai Ichi no Kata (剣体一致の形, "sword and body as one") is the kata in which Minoru Mochizuki paired the sword with the empty hand. Each technique is shown as a sword form and as its empty-hand twin — the same motion expressed two ways. Mochizuki recorded the kata in two versions: a two-form version in 1978 (sword and body), and a three-form version in 1995, which adds a sword-against-unarmed mode.

Origins: the sword before the aiki

The Ken-tai Ichi no Kata pairs sword technique with empty-hand technique. Mochizuki could build it because he had trained classical sword long before he met Morihei Ueshiba and took up aiki. In Nihonden Jūjutsu (1978) he says so plainly: 

Fortunately, I had acquired the old sword methods before I studied aiki-jūjutsu, so I was able to know the interrelation, at the level of technique, between kenjutsu and jūjutsu. 

The sword understanding he brought to that work was already substantial: 

• 1907 — Minoru Mochizuki is born in Shizuoka (11 April). 
• 1912 — begins jūdō. 
• 1918 — enters the dojo of Daichō Kurō — the Bushūkan — and begins kendō. Daichō was the ninth-generation master of Rikishin-ryū (力信流), a comprehensive old school of jūjutsu, kenjutsu, bōjutsu, and iai. 
• 1925 — trains Gyokushin-ryū (玉心流) jūjutsu, receiving its kirigami. 
• 1928 — joins the Kobudō Research Society (古武道研究会) founded by Jigorō Kanō at the Kōdōkan, and trains Tenshin Shōden Katori Shintō-ryū kenjutsu. In the same year he enters Nakayama Hakudō's Yūshinkan (有信館) and begins iai in the Musō Shinden-ryū line. 
• 1930 — sent by Kanō to Morihei Ueshiba; begins aiki (then Daitō-ryū). 

By the time he took up aiki, Mochizuki already held Rikishin-ryū kendō, Katori Shintō-ryū kenjutsu, and Nakayama Hakudō's iai. The Ken-tai Ichi no Kata is what he made when he set that sword knowledge against the aiki body-technique he learned afterward.

The record of the kata

c. 1968 — By his own account in Nihonden Jūjutsu (written "about ten years" later), Mochizuki codifies the Ken-tai Ichi no Kata. 

1978 — Nihonden Jūjutsu (Kōdansha, 24 December). The kata appears in two forms — sword and body. Mochizuki describes having "codified" (seitei) it. He is 71. 

1983 — On 22 November, Mochizuki is interviewed at the Shizuoka Hombu by Stanley Pranin (Aiki News). Demonstration footage dated to the same year shows the kata in two forms. He is 76. 

1985–1987 — Mochizuki makes documented teaching visits to Europe: Montbrison (1985), Aix-en-Provence (1986), and Marignane and Méru (1987), including a seminar he directed in Yoseikan aiki. He is 78–80. 

1995 — "Dō" to "Sen" o wasureta Nihon budō ni katsu (BAB Japan, 15 February). The kata appears in three forms — sword vs sword, sword vs unarmed, and unarmed vs unarmed. Mochizuki writes that he "reconstructed" (fukugen) the sword forms from the empty-hand techniques. He is 87. (Chapter 5, §3, pp. 172–189.) 

1997 — The Yoseikan Sōgō Budō video (BAB Japan) records the kata in three forms. 

2003 — Mochizuki dies (30 May). 

2005 — The 1997 video footage is reissued on DVD.

What the record shows

The Ken-tai Ichi no Kata is recorded in two forms in 1978 and in three forms in 1995. 

The two-form version — each technique shown as sword and body — is documented from the 1978 book through the 1983 footage. The three-form version adds a middle mode, sword against unarmed, in which the empty-handed defender takes the technique and disarms the swordsman. This three-form version is documented from the 1995 book. 

The middle mode therefore entered the documented record between 1983 and 1995.

Lineage of Yoseikan sword

Mochizuki trained Tenshin Shōden Katori Shintō-ryū from 1928 as a member of the Kobudō Research Society (古武道研究会) founded by Jigorō Kanō at the Kōdōkan. This is the source of the Yoseikan iai and the Yoseikan kenjutsu. 

He also studied iaidō under Nakayama Hakudō at the Yūshinkan. This is a separate line and does not form part of the Yoseikan paired kata. 

In jūdō, Mochizuki was a student of Jigorō Kanō and Kyūzō Mifune; in aikidō, of Morihei Ueshiba. He records that Ueshiba once told him the Yoseikan was so different from aikidō that he "might as well call it aiki-jūdō." 

In his published notes, Mochizuki documents that he rebuilt the Katori solo iai as paired forms with an attacker, and that he revised individual kata — setting out, in each case, his reasons.

A note on the evidence

The dates above rest on different kinds of source, and it is worth keeping them distinct. 

The 1978 and 1995 dates are taken from the books' colophons, and the 1983 interview is a dated record. These are firm. The pre-1930 training dates follow Mochizuki's documented biography. 

The c. 1968 codification is Mochizuki's own recollection, set down in 1978 — his testimony, rather than an independent record. 

The European visits of 1985–1987 are documented events. Whether surviving European demonstration footage of the three-form kata dates from these visits — which would place the three-form version in the mid-1980s — is not yet established, and depends on confirming the footage's provenance. Until then, the three-form version is documented from 1995.

Sources

Minoru Mochizuki, Nihonden Jūjutsu (日本傳柔術), Tokyo: Kōdansha, 24 December 1978. 

Minoru Mochizuki, "Dō" to "Sen" o wasureta Nihon budō ni katsu (『道』と『戦』を忘れた日本武道に喝), Tokyo: BAB Japan, 15 February 1995. ISBN 4-89422-177-2. 

Stanley Pranin (Aiki News), interview with Minoru Mochizuki, Shizuoka, 22 November 1983.