The Worlds Most Popular Piano. Precise, ultra-responsive touch, clear, full-bodied tone and a reputation for reliability have made U Series pianos the choice of professional musicians, conservatories, teachers, students and music lovers, the world over. Add to that Yamaha's legendary attention to every detail of every piano, and it’s no surprise that the U Series has been the world’s most popular upright for over half a century. The Professional U Series includes the 48" U1 and 52" U3. Contact us for group pricing, current sales & promotions.