So, the question remains, how does the symbolism of two relate to the technique Munenori and Jyubei are talking about? What is key, I think is the way that the shoots diverge. Looking at the pictures, what struck me first, on seeing the tree, was how sword-like the bare branches looked. This was especially noticeable with the amount of blossom and new leaves on all the surrounding trees; in addition, each new branch has its opposite, which diverges at an angle from the main branch. To my mind, this suggests the idea of alternative angles/paths of attack, and this is what may have been in the mind of the Hikita Bungoro when he named the concept (if, indeed, it was actually he who did so).