As the recent Nashville production of Stephen Sondheim’s 40-year-old musical Company proved, when you write a show set in contemporary times, it will naturally begin to date itself almost immediately. On the other hand, if you write a show set in the middle of the 19th century, it’s a period piece, and its datedness is the whole point. Such is the theatrical history lesson that is Sondheim’s Pacific Overtures, first presented on Broadway in 1976. It definitely falls into the category of alternative musical, with its story of American naval adventurism in isolated Japan in 1853, its integration of Kabuki-style performance, and a score that bears almost no resemblance to the tradition of musical theater that greatly influenced its creator. Even the groundbreaking rhythmic and dissonant elements of West Side Story, for which Sondheim provided lyrics, seem somewhat conventional in comparison, as Sondheim boldly merges the sounds of East and West (and never mind Rodgers and Hammerstein). The show is rarely staged anywhere because it demands so much in the way of versatile casting and physical production, but Blackbird Theater impresarios Greg Greene and Wes Driver have boldly accepted the challenge. The large ensemble features talented players with worthy résumés, and the musical direction is by pianist and sometime actor Ben van Diepen. So go — even if only to say you were there.