Sondheim aficionados don't need to be told that today is a significant date for two reasons. First, here in London tonight (following previews from 20 June), the Donmar Warehouse opens its revival of the great man's 1976 East-meets-West musical Pacific Overtures, which stars Jerome Pradon] and Cornell John and is co-produced with the Chicago Shakespeare Theater. Second, back in the Windy City, at the nearby Goodman Theater, Bounce, Sondheim's latest musical (and his first original score in some nine years), receives its world premiere. Coincidentally, the latter reunites the composer and lyricist with two of his key collaborators on the former, book writer John Weidman and director Harold Prince. Bounce has Donmar connections, too. Originally titled Wise Guys, the show started life in 1999 with an Off-Broadway workshop directed by the Donmar's then-artistic director Sam Mendes. Unfortunately, that production, which had been scheduled for a Broadway opening in 2000, never happened, ending acrimoniously with a lawsuit between producer Scott Rudin and Sondheim and Weidman. It was only after legal wrangling ended in 2002 that the creators were able to work on the piece's current incarnation. A musical comedy, Bounce tells the American Gold Rush story of real-life brothers Addison and Wilson Mizner. Whether Bounce will someday add to the long list of Sondheim musicals at the Donmar - Pacific Overtures marks the fifth - and, indeed, whether it receives a Broadway airing, is likely to be heavily influenced by reviews in Chicago and in Washington DC, where it transfers for a limited autumn season.