Lastmonth as shakuhachi tip was about covering the holes precisely. This month I would like to write m ore about covering holes.
There are many ways in which not having keys to cover the holes like a Western silverflute is a benefit for the shakuhachi, but there are also drawbacks. The largest such drawback is that air leakage can occur through not covering holes properly.
For instance, if Tsu sounds good but Ro is weak or nonexistent, there is a strong possibility that air may be leaking out somewhere.
It might not always be the first hole, either,since your body's entire balance can change going from the state when only the first hole is closed to having all holes closed. This may cause some other hole to leak some air.
Air also often leaks from the second hole when making the transition from Ro toTsu-meri or Ro-dai-meri. This is especially true if you are using a long flute and covering the second hole with the pad on your palm just before your index finger.
Air leakage is one cause that people have trouble with meri's, so try again while paying attention to these points.