Japanese music, like Japanese history, changes glacially. In the static world of koto playing, Kazue Sawai and her seven-member ensemble have created shock waves. During the ensemble's performance Thursday night in the Kennedy Center's Terrace Theater, Sawai exposed the koto's deep roots in Japanese courtly traditions, but only to bend and stretch them.

Indeed, bending and stretching is an important part of Sawai's method for playing the koto, the ancient Japanese stringed instrument resembling dulcimers and harps. In addition to pulling strings, a distinctive feature of koto playing is the strange swish produced by running two fingers across the instrument. For this task, Sawai's fingers, and sometimes her whole arm, are called into action. Her techniques -- beating the koto with drumsticks and snapping the strings against its body -- reached their apotheosis in the final work, "Homura," a koto concerto written for her by her husband. The piece fused these delicate and astounding effects into a structure as cohesive and dramatic as any of Bartok's concertos.

Opening with Hideaki Huribayashi's rock-inspired "Aoku," Sawai moved on to "Nocturne," a piece that followed the old form of alternating sections in vocal style with rhythmic expansions.

Immediately dispensing with this introspective and faintly aristocratic mood, Hiroshi Yoshimura's "Clouds for Alma" whizzed into the world of Steve Reich and the minimalists. Another Western experimenter exerting influence was John Cage. At times, especially during the concerto, Sawai's altered kotos made themselves heard as the Japanese counterpart to prepared piano. The Cage connections were also in evidence during a piece by former Cage colleague Christian Wolff. Now a composer of political music, Wolff has certainly found his metier in "Malvina." Playing this solo, Sawai builds his soft, sparing melody to a wood-smacking frenzy -- ultimately dismantling 11 centuries of tradition.