Balanchine said of Swan Lake, the only ballet about which almost everyone knows something, “It’s nonsense.” Off the record, though, the great choreographer made deep sense of this treasure, and not only sideways in his own, plotless, Tchaikovsky ballets. He reduced hours of story—which he wittily summed up as “young prince falls in love with a girl-swan, and naturally nothing good comes of it”—to little over a half hour. He reduced in the culinary sense, to essence and bone. It’s as if the plaintive verse of Keats, lush with birds and flowers, were devoured by the “widening gyre” of Yeats, in which “innocence is drowned.” Gone are the birthday party, folk dances, glamorous wicked Odile, and even a return to the lake. Instead, black Art Deco swans constantly shift ranks like slippery tides while the angular girl-swan Odette resists, then submits, to intransigent destiny. The 1951 Swan Lake appears on the New York City Ballet “All Balanchine I” program with the thoroughly pleasant, mildly comic Donizetti Variations and the fleet, romantic Ballade. —Apollinaire Scherr