In Aikido, everything comes out of three ki‘s: Sho-Chiku-Bai [Pine – Bamboo – Plum]. These are, to state them in one breath – if I may say – iku-musubi, taru-musubi, and tamatsume-musubi.
Now, the [ki of the] Bai [plum] of Sho-Chiku-Bai, coming from the [direction of joy: the] North-West, which is also the place of hearing the Dharma, is, after all, about a teaching , and it is about [standing on] Ame-no-Ukihashi. And this is precisely because “bai” [the plum] is triangular in nature.
Then, moving on, [the ki of] Sho [pine], being the place where there is no ura or omote, is spoken of as katsuhayabi, and its teaching is the teaching of Miroku. It is also the ongoing manifestation of the true Great God’s “su”. “Su”, of course, with the Original Great Spirit, [who was there at the beginning], is simply the ongoing manifestation of the heart and form of that [same] Great God.
Now, in addition, we say that “sho” [the pine] means shikaku, and, indeed, at the time that Shikoku was formed (or Iyo-no-Futana-no-Shima to give it its old name), the long out-breath [of Izanagi no Mikoto and Izanami no Mikoto], as it became water vapor, rose up into the sky, and spread out throughout the entire heavens. Because this ki rose up like this: in the shape of a triangle, what we call Budo emerges out of this [same] ki: when you make the ki of your soul to be like this ki. That is, you make your soul enter into this ki.
Aikido, of course, is the training of souls, precisely because when you inscribe a “+” [i.e. link the kokyu of heaven and earth, thus automatically creating, too, horizontal musubi,] in the center of the circle [of a meditative state of mind] you create something like four triangles. This is your soul becoming tsurugi and yari [a sacred sword and a spear].
But in the end, of course, “sho” [the pine] is a teaching, and the teaching of Miroku, and the teaching of the non-existence of ura and omote, and [being in touch with the feeling of] tamatsume-no-musubi.
Now, along with this, [the ki of] Bai [plum] means that the three Gods of Creation [Ame-no-mi-naka-nushi-no-O-Kami, Takami-musubi-no-O-Kami, Kami-musubi-no-O-Kami – or: center, yang, yin] [are in you], and through sangaku-ho , using them, the coming together of the beginnings of Budo can be understood. Such that, becoming ittai with these triangles, you acquire invincible bodily strength. This is the way to develop bodily strength that can absolutely not be broken down.
Now by definition – right from the beginning – what we call [the ki of] Chiku [bamboo] is training [to develop strong] ki. Developing ki through shu-gyo is a matter for the great god, Susanoo-no-Mikoto. He is the great king of strength. He is the great king of budo.
– – – O’Sensei – probably audio-recorded by by Masatake Fujita, transcribed by Sadateru Arikawa Shihan, published in Aiki-Shinzui, pp.21-22