The opening of the Ninth Street Show, otherwise known as the 9th Street Art Exhibition: A gathering of a number of notable artists, and the stepping-out of the post war New York avant-garde, collectively known as the New York School.

The 9th Street Art Exhibition of Paintings and Sculpture is the official title artist Franz Kline hand-lettered onto the poster he designed for the Ninth Street Show. Now considered historic, the artist-led exhibition marked the formal debut of Abstract Expressionism, and the first American art movement with international influence. The School of Paris, long the headquarters of the global art market, typically launched new movements, so there was both financial and cultural fall-out when all the excitement was suddenly emanating from New York. The postwar New York avant-garde, artists like Willem de Kooning and Jackson Pollock, would soon become "art stars," commanding large sums and international attention. The Ninth Street Show marked their "stepping-out," and that of nearly 75 other artists, including Harry Jackson, Helen Frankenthaler, Michael Goldberg, Joan Mitchell, Grace Hartigan, Robert De Niro Sr., John Ferren, Philip Guston, Elaine de Kooning, Louis Schanker, Lee Krasner, Franz Kline, Ad Reinhardt, Ludwig Sander, David Smith, Milton Resnick, Joop Sanders, Robert Motherwell, Barnett Newman, and many others who were then mostly unknown to an art establishment that ignored experimental art without a ready market.