Christopher Swan, Donna Gerdes and Megan DeLay in Banyan Theater Company’s The Piano Teacher.
When the curtain rises on Julia Cho’s The Piano Teacher (now playing at the Cook Theatre in a Banyan Theater Company production), the audience is at first lulled into a sense of old-fashioned coziness, as the elderly woman at center stage begins talking in gentle, bemused tones directly to us, even coming out into the auditorium at one point to dispense cookies. What could be more reminiscent of a certain kind of dimly remembered past than the somewhat shabby, fusty room she lives in, or the way she begins to recollect the many children she taught piano there over more than 30 years? Chances are we all have a Mrs. K., as she calls herself, in our lives, even though we may have almost forgotten her.

