Elegance: beginnings and endings
A lot of attention is given to developing diminuendos in honkyoku phrasing. How you start notes is important too, and how they are brought into existence affects the whole feel of the phrase and the piece. The two main dynamic approaches to koten honkyoku, kyosui and kusabibuki, involve different dynamics at the beginnings of phrases. But they both benefit from elegant sound production.
Gentling the note from silence into sound, without unwanted breathy artifacts or rough passage, contributes to the elegance of the musical phrasing, especially when combined with smooth and elegant diminuendos.
Kyosui or natural breath is the easier form to make with elegance. The sound is simple and there is a natural emphasis at the beginnings of phrases.
With kusabibuki, or wedge-shaped phrasing, the initial notes need to be strong to form the top of the wedge. Even a strong burst of sound can be made elegant by exerting control over the embouchure. Start with lips slightly open and soft, and quickly narrow the blowing nozzle. This gives a smoother start to the sound. Atari is often used to reinforce kusabibuki technique, but it should not mask the elegance of the sound.
Shakuhachi has a wonderful range of breath effects available to the player. It's best to learn how to make them bend to your will, rather than you bending to their will.