I have cheaper shamisen and it wears from lots of use in positions 3 and 4 San no hito, have tried an epoxy filler which is ok but for longer term fix shall I take off 5mm from top of Sao and fit denser hard wood or stainless steel flat bar? Do expensive shamisens have the same wear problems?
Hi Brian!
Hmmm… interesting. Yeah, I believe all shamisen, even with kouki sao, have wear problems which must be planed (a process called “kanberi”) to remove the depressions. However, the cheaper karin wood is much softer and so will wear quicker.
shall I take off 5mm from top of Sao and fit denser hard wood or stainless steel flat bar?
If you can make the the hardwood/bar fit flush in (so there isn’t a bump or ridge where it and the sao connect), and you aren’t fine with how it looks, I think that would be a fine idea. A reinforced shamisen! 
Thanks for the input, will try some heart teak wood and upload some pics.
be interesting to see 
i had a couple ideas myself.