My Shakuhachi Tip for 2/2001 was you don’t have to cover the holes quickly if you do it precisely." I would like to speak more about this subject this month.
Some of the fingers used to cover the 5 holes of the shakuhachi are easier to move than others. For example, your index finger is usually fairly dexterous,whereas the thumb is powerful but usually lacks this dexterity. This is particularly true for the thumb on your non-dominant hand.
Despite this, it is a fact that most people use the thumb with worse dexterity to cover the 5th hole. Their lack of ability to move the thumb well causes many people problems. However, many people practice moving their thumbs rapidly, and theyeventually become able to hit the 5th hole very quickly.
This can lead to two problems. The first problem is precision. People tend to concentrate too much on moving the thumb rapidly, so they are not actually covering the hole fully. It takes time in the beginning to close the hole fully, and yet many people open the hole back up again before it has been fully closed.
Please be conscientious about covering the hole fully during practice. Don't worry about speed, only precision. You will have a tendency to get faster and faster, but hold the speed back.
The second problem is speed. You can hit the 5th hole slowly or quickly, but increasing the speed just a little bit is a problem. You may intend to or think you are increasing the speed just a little bit at a time, but in reality many people tend to make drastic jumps in speed.
It is as though they can only hit the hole at two speeds, slow and fast. However, if you can practice to the point where you also master all the speeds in between, your sound will improve greatly.
So,practice at many speeds, and practice increasing and decreasing speed gradually and smoothly. If in the middle of this practice you notice your precision suffering, drop down to a slower speed again.
It's very difficult to correct bad habits. Return to the fundamentals and practice precisely.