Impromptu No. 4

"Impromptu No. 4" of 1951, executed in wood-and-object print technique, is one of Onchi's most freely expressive compositions — the "impromptu" title signaling a work made with maximum spontaneity and minimum premeditation, allowing the formal properties of the printing materials to guide the outcome. This improvisational approach, borrowed from musical practice, represented Onchi's most avant-garde method: releasing control to allow the printing process itself to generate the composition. The object print technique, incorporating actual found materials, further emphasized the element of chance.