My advice for 「July of 2000」touched on the phenomenon of fast phrases not sounding smooth because “notes of the phrase are not spaced evenly”. The cause for this which I posited then was the speed at which different fingers move not being the same. Now I would like to offeranother cause for consideration.
Unlike the western silver flute, the shakuhachi has no keys to close holes. Since with the shakuhachi we must close the holes with our fingers, sometimes this results in taking too much time to close the holes completely, even by a matter of milliseconds.
In other words, the way we close the hole with the pad of our finger can be imprecise. What I mean by closing a hole precisely is that the pad of the finger covers the entire circumference of the hole at exactly the same instant.
If you take your shakuhachi in hand and try tapping a hole, you will see that tapping it exactly results in a reverberating hollow sound. Hitting the hole imprecisely doesn't produce this sound. It is this slight difference which can ruin a note within a fast phrase.
Even if your fingers are moving quickly and at even speed, if the pad of your finger doesn’t close the hole in a precise manner – the entire circumference simultaneously – then the phrase won’t come together as it should.
The other side of this is that even if you don’t play the notes in sequence very quickly, but do play them precisely, then the phrase will come together better than you might expect.
The key to this is repetition. Drill the position of the holes into your muscle memory by repetition such that you get that hollow reverberating sound even when you relax your fingers and tap the holes lightly.