The Dai-Nippon Teikoku Kendō Kata (later the Nihon Kendō Kata) were not the first attempt by the Butokukai at creating a set of common sword forms. Already in December 1906, three kata called the Dai-Nippon Butokukai Seitei Kenjutsu Kata (大日本武徳会制定剣術形) were announced by a committee of seven high-ranking (hanshi all) members led by Watanabe Nobori-hanshi of Shintō Munen-ryū. However, they were never widely disseminated due to dissatisfaction with unresolved arguments within the committee, the feeling being that Watanabe had used his influence to push decisions without sufficient discussion.
Each of the three Butokukai kenjutsu kata used a kamae symbolising one of the three parts of the universe: Heaven (天, ten), represented by jōdan; Earth (地, chi), represented by chūdan1; and Humanity (人, jin), represented by gedan2. The same philosophical metaphor can be seen in the choice of kamae for the three kata later created by the Ministry of Education and Culture and included as the first three forms of the current kendō kata.
These articles are mainly based on the manual (published in April 1912) by Naitō Takaharu and Monna Tadashi, both of Hokushin Ittō-ryū and representatives of the Butokukai headquarters on the Kendō Kata Creation Committee in 1911-1912.
Although the Butokukai seitei kenjutsu kata were intended to cross ryūha borders and allow members of different schools to practise a unified set of kata together, there appears to have been an outsize influence of Shintō Munen-ryū on the final forms. Three out of seven members of the committee, including Watanabe himself, were from that school, and the dissatisfaction from other committee members and the subsequent reluctance among instructors to adopt the new kata in all likelihood stemmed from this fact. Fortunately for us, however, that does allow us to reference the sparse (read: single source) extant documentation against corresponding techniques in Shintō Munen-ryū, and I have included commentary to that effect. These notes are clearly marked as such, and I have otherwise striven to keep the translation clean and free from bias.