In the summer of 1902, Kandinsky invited Gabriele Münter to join him at his summer painting classes just south of Munich in the Alps. She accepted the offer and their relationship became more personal than professional.
It was during this time that he began to emerge as an art theorist as well as a painter. The number of his existing paintings increased at the beginning of the 20th century; much remains of the landscapes and towns he painted, using broad swaths of colour and recognisable forms. For the most part, however, Kandinsky's paintings did not feature any human figures; an exception is Sunday, Old Russia (1904), in which Kandinsky recreates a highly colourful (and fanciful) view of peasants and nobles in front of the walls of a town. Couple on Horseback (1907) depicts a man on horseback, holding a woman as they ride past a Russian town with luminous walls across a blue river. The horse is muted while the leaves in the trees, the town, and the reflections in the river glisten with spots of colour and brightness. This work demonstrates the influence of pointillism in the way the depth of field is collapsed into a flat, luminescent surface. Fauvism is also apparent in these early works. Colours are used to express Kandinsky's experience of subject matter, not to describe objective nature.
Perhaps the most important of his paintings from the first decade of the 1900s was The Blue Rider (1903), which shows a small cloaked figure on a speeding horse rushing through a rocky meadow. The rider's cloak is medium blue, which casts a darker-blue shadow. In the foreground are more amorphous blue shadows, the counterparts of the fall trees in the background. The blue rider in the painting is prominent (but not clearly defined), and the horse has an unnatural gait. This intentional disjunction, allowing viewers to participate in the creation of the artwork, became an increasingly conscious technique used by Kandinsky in subsequent years; it culminated in the abstract works of the 1911–1914 period. In The Blue Rider, Kandinsky shows the rider more as a series of colours than in specific detail. This painting is not exceptional in that regard when compared with contemporary painters, but it shows the direction Kandinsky would take only a few years later.
From 1906 to 1908, Kandinsky spent a great deal of time travelling across Europe (he was an associate of the Blue Rose symbolist group of Moscow) until he settled in the small Bavarian town of Murnau. In 1908, he bought a copy of Thought-Forms by Annie Besant and Charles Webster Leadbeater. In 1909, he joined the Theosophical Society. The Blue Mountain (1908–1909) was painted at this time, demonstrating his trend toward abstraction. A mountain of blue is flanked by two broad trees, one yellow and one red. A procession, with three riders and several others, crosses at the bottom. The faces, clothing, and saddles of the riders are each a single colour, and neither they nor the walking figures display any real detail. The flat planes and the contours also are indicative of Fauvist influence. The broad use of colour in The Blue Mountain illustrates Kandinsky's inclination toward an art in which colour is presented independently of form, and in which each colour is given equal attention. The composition is more planar; the painting is divided into four sections: the sky, the red tree, the yellow tree, and the blue mountain with the three riders.
In 1909, Wassily Kandinsky witnessed a presentation Aleksandra Unkovskaya made (at the Theosophical Congress in Budapest) regarding her innovative system in music education, sound-to-colour synesthesia or Chromesthesia which is a type of synesthesia in which sound involuntarily evokes an experience of colour, shape and movement, which led to his own discoveries in his art. Kandinsky stated: "to impress a tune upon unmusical children with the help of colours ... She (Unkovskaya) has constructed a special, precise method of 'translating' the colorus of nature into music, of painting the sounds of nature, of seeing sounds." This transcended the spiritual in art and led him to develop the concept and formula of a chain reaction experience (reciprocal relationship/artist and viewer): "Emotion — sensation — the work of art — sensation — emotion." The concept was based on the principle of the resonance of string instruments.
