There are many times in shakuhachi music where you are called on to hit(also called “push”) a certain hole one or more times to repeat a note. The way the hole is hit determines how the repeat sounds, and sometimes poses difficulties.
Sometimes, if the hole is not hit precisely enough, the repeat sound will become muddied. There are two parts to hitting the repeat hole precisely:closing the hole precisely and opening it precisely. Opening the hole precisely isn’t problematic for most people, but closing the hole precisely can be surprisingly difficult.
In order to do this, the pad of your finger should touch all sides of the hole at once. It should not hit one side any sooner than any other. To do so –even by a little bit – will result in the muddy sound we are trying to avoid.
The secret to precisely covering the entire hole perfectly simultaneously is relaxing. As an experiment, try hitting a hole on your shakuhachi - without blowing on it - while relaxing your finger. If you get a deep reverberating sound, you know you are closing the hole sufficiently accurately.
This is crucial for techniques like “koro-koro” and hitting the 5th hole repeatedly.