<html> Ben, I have had the same experience with breaking treble strings in all brands of pianos.  I remember a petite little Korean girl who had a Steinway B that was a rat's nest of broken wire when I first got to it.  It is not a Yamaha problem.  The strings are simply tired.  I consider it to be a sign of a good pianist, practicing hard towards some kind of goal, like a competition or recital.  If you check, I'd guess they are working on some difficult Chopin right now. Here is the answer that really does help: 1. The strings in the section are tired, and will need to be replaced. 2. Shape the hammers and regulate the action. If these things are done, the piano will behave like new again, and the pianist will have restored faith in their piano. Don Mannino RPT </html>