During his studies in Berlin, Döblin had written his second novel, Der Schwarze Vorhang (The Black Curtain). The novel portrays the developing sexuality of its protagonist, Johannes, and explores the themes of love, hate, and sadism; in its use of literary montage, The Black Curtain already presages the radical techniques that Döblin would later pioneer in Berlin Alexanderplatz. Introduced by a mutual acquaintance, Döblin met Georg Lewin, a music student better known as Herwarth Walden, who founded the Expressionist journal Der Sturm in 1910. Der Sturm, modeled after Karl Kraus's newspaper Die Fackel (The Torch), would soon count Döblin among its most involved contributors, and provided him with a venue for the publication of numerous literary and essayistic contributions. Through Walden Döblin made the acquaintance of poet Else Lasker-Schüler. At regular meetings at the Café des Westens on Kurfürstendamm or at the wine bar Dalbelli, Döblin got to know the circle of artists and intellectuals that would become central to the Expressionist movement in Berlin, including Peter Hille, Richard Dehmel, Erich Mühsam, Paul Scheerbart, and Frank Wedekind, among others. In October 1911 he met the Painter Ernst Ludwig Kirchner, who painted several portraits of Döblin between 1912 and 1914 and illustrated some of Döblin's literary works. Döblin's early novel Der Schwarze Vorhang was published in Der Sturm, and in November 1912 the Munich publishing house Georg Müller published his collection of novellas under the title Die Ermordung einer Butterblume und andere Erzählungen. In May 1913, he completed his third novel The Three Leaps of Wang Lun (Die drei Sprünge des Wang-lun). Published in 1916, this historical novel about political uprising in 18th-century China was a literary breakthrough for Döblin, earning him literary acclaim, public recognition, and the prestigious Fontane Prize. He began writing Wadzeks Kampf mit der Dampfturbine (Wadzek's Struggle with the Steam Turbine) the following year, completing it by December 1914 although it was not published until 1918.