Two women. Two cultures. One music.

The word sensei in Japanese literally means "one who came before," but that's not what Janet Pocorobba's teacher wanted to be called. She used her first name, Western-style. She wore a velour Beatles cap and leather jacket, and she taught foreigners, in English, the three-stringed shamisen, an instrument that fell out of tune as soon as you started to play it.

Vexed by the music and Sensei's mission to upend an elite musical system, Pocorobba, on the cusp of thirty, gives up her return ticket home to become a lifelong student of her teacher. She is eventually featured in Japan Cosmo as one of the most accomplished gaijin, "outside people," to play the instrument.

Part memoir, part biography of her Sensei, The Fourth String looks back on the initial few years of that apprenticeship, one that Janet's own female English students advised her was "wife training," steeped in obedience, loyalty, and duty. Even with her maverick teacher, Janet is challenged by group hierarchies, obscure traditions, and the tricky spaces of silence in Japanese life.