shamisen bridge
The small wooden piece placed on the skin of a shamisen that supports the strings and transmits vibration.
If the shamisen bridge shifts, the sound changes.
General term for a bridge on a stringed instrument; 三味線の駒 specifies the shamisen bridge.
The three-stringed Japanese instrument itself; 三味線の駒 is a part of it.
Compound of 三味線 (shamisen) and 駒 (bridge). The exact historical derivation is straightforward; the term is a literal description of the part.