The upper joint body is drilled out slightly larger, where a thin ebonite pipe with an oboe bore is adhered. Ebonite is an excellent material for wind instruments, as is proven with top-grade mouthpieces for saxophones and clarinets as well as bassoon liners. Much knowledge was derived from our own bassoon manufacturing, and with further engineering, Yamaha successfully developed oboes with the reliability and warmth of wood.
Every tone-hole (except metal octave vents) is lined with POM resin for air-tight, stable contact between each pad. In the rare event that the wood should crack, the damage to the tone-hole profile and intonation would be minimal thanks to the inserts.
The trademark logo is engraved on the back of the upper joint.