"The streets shall be our brushes - the squares our palettes," proclaimed the Russian poet Vladimir Mayakovsky in 1917.

So went a rallying cry for a generation of painters, notably Kazimir Malevich and Alexander Rodchenko, quick to hammer out their aesthetic beliefs on the anvil of the Russian revolution. "Down with art as a beautiful patch on the squalid life of the rich!" roared Rodchenko. "The picture," Malevich stated less stridently " - paint, colour - lies inside our organism." With avant-gardists, it is generally best to assume their bark was worse than their bite. At Berlin's Martin-Gropius-Bau, a unique collection of works from a hugely energetic cultural period in Russia, from the middle of the first world war to the late 1920s, allows us to see how convinced of their mission these artists were, and how tragically short-lived it was. The collection, including gadgetry, porcelain and objets, belonged to George Costakis, a Moscow-born Greek who, after the second world war, collected - a remarkable story in itself - the works on display, representative of art reviled, by then, by Stalin and his culture-ghouls. Costakis emigrated to Greece in 1977, and took with him paintings and drawings that bear witness to an inventiveness equal to Picasso and Braque's Cubism, and the Vienna secessionists.

One is continually struck by the sheer beauty of the artefacts, even if the force of the thinking behind them - constructivism, suprematism - has faded. Malevich's small "Black Quadrilateral", a black oblong on white, immediately announces the movement's austerity. In the same room, Mikhail Plaksin's 1922 canvas "Planetary" is a stunning abstract of reds and greens with a surrealist dreaminess.

Plaksin is one of many unfamiliar names enjoying company with the more famous Malevich and Rodchenko. The versatility of Ivan Kliun, for one - landscapes, structures of pure colour, geometric meditations - is a revelation. Works for which alone I would visit the show are El Lissitzky's 1921 lithograph "Radio Announcer" and two Kandinsky teacups (1921, 1923), exquisite items by Russia's greatest abstractionist.

This is a magnificently informative exhibition, inviting us to relish the burst of an avant-garde star in the east before it vanished into the black hole of Stalinism.

Until January 10 2005. The exhibition travels to Vienna and Thessaloniki.

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