The “highly important” artwork by the famed artist was acquired by the Edinburgh gallery thanks to a donation made by collectors Henry and Sula Walton.
Head, which dates from 1912 during Picasso’s cubist period, is a large charcoal drawing.
Experts say drawings from this crucial period in Picasso’s career are extremely rare and the larger works, such as Head, which measures 64.9 x 49.5 cm, are nearly all in museum collections.
The late Henry Walton was Professor of Psychiatry and Professor of International Medical Education at Edinburgh University, his wife Dr Sula Wolff was an eminent Consultant Child Psychiatrist and the author of internationally acclaimed books on child psychiatry.
Henry, who died in 2012 and Sula, who died in 2009, bequeathed their art collection to the gallery, but they also established the Henry and Sula Walton Charitable Fund, specifically to help the Scottish National Gallery of Modern Art make new and important acquisitions.
They were particularly passionate about Picasso’s work, assembling a collection of more than a dozen prints by the artist.
Picasso hoarded huge numbers of his drawings, and at his death in 1973, most of them passed to the French state and in turn became part of the new Musee Picasso in Paris.
This drawing belonged to Picasso’s grand-daughter, Marina Picasso, from whom it was purchased by Jan Krugier (1924-2008), one of the world’s leading dealers in modern art.
He kept it for his own collection. His celebrated collection of drawings was offered for sale at a Sotheby’s auction in London in February this year and the gallery acquired it there.
The gallery now boasts a world-class group of works by Picasso.
The drawing relates to several works by Picasso already in the collection: a collage Head, 1913; and the large Weeping Woman etching of 1937.
Simon Groom, Director of the Gallery of Modern Art said today/yesterday [THURS]: “I think Henry and Sula Walton would have been thrilled by this acquisition.
“They were passionate about art, passionate about the Gallery, and passionate that the very greatest artworks should be available for our visitors to see.
“This drawing lies right at the start of modern art. It is bold, dramatic and hugely inventive: with works such as this Picasso completely re-wrote the rules on art.
“There are comparable drawings in museums in Paris and New York, but nothing like it in any UK public collection. I think Henry and Sula would have been proud to change that.”
Picasso’s cubist work dates from about 1907 to 1915.
Rather than try to copy nature, Picasso was interested in recreating it by pulling it apart and recomposing it.
Part of the impetus behind cubism comes from the desire to view an object from different sides, and re-compose these different views in a single picture.
Cubism is arguably the most important development in art since the Renaissance, and its influence on art and design can hardly be over-estimated.
Prof Elizabeth Cowling, a world-renowned expert on Picasso, will deliver a lunchtime talk on the work in the Studio, at the Gallery of Modern Art on 14 April at 12.45, admission is free.