Just some feedback from a repair last summer. I tweaked a nice old Tadatsuke 1.8 that was not responding well for the owner. You can see the Tadatsuke Hanko on the left. A Gyokusi on the right.

“Perry, what you did is a @#$%&*^  miracle!

My shakuhachi arrived this morning and I immediately tried it out.  Right from the start I was playing at 442 with the only pitch exceptions being my fault - I need to get used to the flute again after taking such a long break from it (almost a year).  Taking off some of the front top edge has made a world of difference.  The angle of the top and the depth of the utaguchi is now perfect for my embouchure.  I also get a much fuller sound and I no longer feel I’m in a struggle with this shak.  I’m amazed at how well you diagnosed the problem after only a very brief description of my experience with the flute. I’m more than pleased with the work you did.  I’m only sorry that I didn’t send it to you sooner.
To even make matters better, the change you made looks so natural that I had to look at the before pictures to see what was different.  I’d recommend you to anyone who has a problem with their flute.
1000 Domos,
- L.G. Colorado

As always, I base my tuning and adjustment choices on what I think the original maker intended, not the demands of the modern musical world 40 or 50 years after the flute was made (unless that’s what the experienced player wants). It should be known that fine shakuhachi craftsmen labor intensively over their instruments. A unique tone can be lost forever in insensitive hands, Please feel free to ask about your old flute. I offer free evaluations.

Namaste, Perry