Continuing under the direction of Michael Blakemore, it opened on Broadway at the Royale Theatre on 11 April and ran for 326 performances. Starring Philip Bosco as Bohr, Michael Cumpsty as Heisenberg and Blair Brown as Margrethe, it went on to win the Tony Award for Best Play, along with two others for Best Featured Actress in a Play (Blair Brown), and Best Direction of a Play (Michael Blakemore). But even for its success, Frayn admitted in an article that "A number of commentators expressed misgivings about the whole enterprise." Several critics noted that it was heavy with scientific dialogue, a little too heavy for the common audience. Though a writer from Physics World hailed it as "brilliant theatre ", a Charles Spencer, of the Daily Telegraph, wrote, "I felt that my brain was being stretched to breaking point—well beyond breaking point, in fact."