The instrument shown is a viola, a close cousin to the violin but distinguishable by its slightly larger size and deeper, richer sound. Like the violin, the viola is played with a bow and features four strings, but it is tuned a fifth lower, giving it a unique tonal quality. This instrument plays a crucial role in orchestras and chamber music ensembles, bridging the sonic gap between the bright, high pitches of the violin and the robust, low tones of the cello. Its ability to provide this middle voice adds depth and complexity to musical compositions, making it an indispensable part of many classical music pieces.