Assertion: piano's soundboard | /r/HasProperty | built into the case
Facets:
Source sentences:
text: Dolge describes Mendelssohn's pedal mechanism: "The keyboard for pedaling was placed under the keyboard for manual playing, had 29 notes and was connected with an action placed at the back of the piano where a special soundboard, covered with 29 strings, was built into the case".
text: Schumann preferred an upright pedal piano, and his pedal keyboard had 29 notes and was connected with an action placed at the back of the piano where a special soundboard, covered with 29 strings, was built into the case.