Sarah Ruhl, the author of The Oldest Boy, and Rebecca Taichman, its director, have known each other for almost a decade, but the new play, which involves an inter-cultural couple’s choice in the context of Tibetan Buddhism, marks an especially significant moment in their collaboration. “When Sarah first gave me the play,” Taichman told me the other day, as we sat in the Mitzi E. Newhouse Theater, “I wept.”

I didn’t press Taichman as to whether she shed real tears. She told me later in the interview that “theater is heavily reliant on metaphor,” so it doesn’t really matter if her weeping was real or figurative: either way, it mattered.

It mattered because, Taichman said, “the play was a wonderful invitation to dive into a subject that has become more personally important to me.” In March, she will be marrying her German boyfriend, Jan Seele. “My boyfriend practices a Tibetan form of Buddhism,” Taichman said. “I’ve learned an enormous amount from him. The play has been a chance to learn more.”

As part of her learning curve, Taichman went on a Buddhist retreat this past summer. She also benefited greatly from the three-week workshop of the play that LCT sponsored before official rehearsals began in September. “The cast presented on a variety of topics,” Taichman said. “Everyone did a great deal of research and we all taught each other. Working on this play has been collaborative in the extreme. When you have actors this talented, a writer this brilliant – you’d have to be crazy not to collaborate deeply as a company.” She added: “We’ve been especially fortunate to have in our cast Tsering Dorjee, who has dedicated his life to the preservation of Tibetan culture. He has taught us a great deal and has been an inspiration every step of the way.”

Staging a play involving spiritual practice is a challenge. “As a director,” Taichman told me, “I feel a responsibility to be authentic, but at the same time I don’t want to put things onstage that don’t belong onstage.” A crucial question, she continued, was: “Are you taking something meant for a totally different context” – religious ceremony – “and doing violence to it?” Taichman and Ruhl have taken great care to be respectful toward Tibetan Buddhism, while constantly reminding themselves, as Taichman put it, “that we are telling a very specific story and that story needs to drive all our choices.”

Taichman met Ruhl at the Woolly Mammoth Theatre Company, in Washington, D.C., at the instigation of Howard Shalwitz, the group’s artistic director.  Their initial collaboration involved Ruhl’s play The Clean House. Taichman sees The Oldest Boy as a continuation of a theme Ruhl has been exploring over the years: spiritual longing.

But Taichman, who grew up on Long Island, attended McGill University as an undergraduate, and went to Yale for her MFA, said the new work is also a departure. “Sarah is the mother of three now, and The Oldest Boy deals with some of the biggest, most daunting and mysterious questions of how to parent.” Taichman continued: “The question every parent must face sooner or later, and that Sarah is asking in this play, is: How do you let your child go?”

Brendan Lemon is the American theater critic for the Financial Times and the editor of lemonwade.com