An extremely fine and  rare impression, with barbs, pulled  with a rich plate-tone on thick wove paper. This is certainly a rare contemporary proof curated by Boccioni himself, as demonstrated by the unquestionable authenticity of the signature. Catalogable as  c-d / f variant, according to the Bellini classification.

With large margins, in fine condition.

The hypothesis that  he who has been portrayed is Sironi, a good friend of Boccioni, was originally put forward by Luigi Bartolini and confirmed by Ettore Sironi, brother of the artist.

References:
J. Taylor, The Graphic Work of Umberto Boccioni, New York, 1961.
P. Bellini, Umberto Boccioni. Catalogo ragionato delle incisioni, degli ex libris, dei manifesti e delle illustrazioni, Cinisello Balsamo, 2004.
M. Calvesi and A. Dambruoso. Umberto Boccioni. Catalogo Generale delle Opere, Turin, 2016; 2 vols.