The German Picasso

His Striding into the Sea of that year, a six-foot stretch of jumbled dunes and wayward perspective peopled by a couple of simple symbolic nudes, makes the point well enough: the drawing is elementary, the space confused, the brushwork a now characteristically irregular and uneven system of hatching, criss-crossing and scrubbing, the colour reduced to purples, greens and ochres.

It is in these last that the interest lies, for only the purple can be classified as a specifically Expressionist colour and it is brought very close in tone to the green and ochre. In these colours there is no sense of shock. This is no match for Munch - hardly even for Duncan Grant, who, in 1912, could have passed as a minor Expressionist.

Kirchner was later to introduce quite startling pinks, but in the main even these are under strong tonal control, except when his paintings have been heavily varnished and are displayed in spotlights. I am inclined to suggest that he prepared his canvases with a thin and absorbent priming that soaked oil from the paint on its surface and left it matt, knowing that this would give him precisely the tone that he envisaged in his mind's eye.

I am also inclined to say that his pictures should never be heavily varnished, if, indeed, varnished at all, for - as with Toulouse-Lautrec's paintings on board - the intended softness of tone is sharpened and broken by any varnish that intensifies the colour and gives it glister. Both his Striding into the Sea and his Artillerymen in the Shower of 1915, demonstrate, more rather than less, how the surfaces of Kirchner's paintings should be.

In this shower painting Kirchner's feathery brushstrokes and their employment as a device to model form are fully apparent. His paint is both substantial, drily catching the grain of the surface beneath (the weave of the canvas or the ridges of earlier brushstrokes), and astonishingly fluid in that it can flow like milk and yet be so full of pigment that it is opaque - the sense of water running on naked flesh is perfectly expressed in the drippage from the penis of the standing figure on the right.

But where is the expression of emotion that we are instructed to expect in Expressionist painting? 1915 was the first full year of the Great War and Germany was already accustomed to wounds and mutilation, fleas, lice and foot rot in the trenches, yet here we have a platoon of naked boys, many as pretty as girls (this is a painting that would hang happily with the mutant adolescents of the Chapman brothers), with not the slightest hint of angst, but in the merry mood of schoolboys at a health and efficiency camp.

The subtitle of this exhibition is Expressionism in the City, by which is meant Berlin, the rich and culturally rich capital of a country that felt expansionist and powerful enough to plunge Europe into what was to become the First World War. Should we see decadence in Kirchner's cabaret and circus subjects, a Gˆtterdˆmmerung impending?

Should we see a prostitute in every well-dressed woman, a Jew behind every hooked nose? Should we see in his many street scenes some evidence of a passionate protest that we can no longer identify? If so, then Kirchner is no match for Dix and Grosz, a decade or so younger and infinitely more powerful and specific in their responses to war, its aftermath and the subsequent moral decadence of Berlin, neither of them Expressionists but capable of far more desperate expression.

Kirchner emerges from this exhibition as far from "the greatest exponent of early 20th-century figurative Expressionism", the claim made by the Academy's president.

Limited by the gestural mannerisms with which he used his brushes, limited by his habitually scribbled draughtsmanship, limited by his naive mismanagement of space, we are left with paintings that seem to have been impetuously produced without correction, by a painter who always stood too close to his easel and never stepped away from it to consider his next stroke.

I cannot discern the raw primitivism that others see; in his sculpture, the influence of ethnic art is evident enough, stylistically putting a little fire in his belly, but that intellectual fire was not transferred to his painting, in which the rawness is that of the incompetent and the primitivism that of the slightly mad.

I cannot see that there is in his pictures any evidence of a romantic nostalgia for a pre-industrial Berlin - only a naive rejoicing in nature and nakedness that was very much the German spirit of the day.

Readily, I can see the seeds of madness in his work. Perhaps the most interesting thing about Kirchner is his crossing the line between his decision to simulate a nervous breakdown in 1915 as a response to military service and the real madness that followed with paralysis and addictions to morphine and alcohol, the charade long out of control. In spite of its near calamitous effects, his success in the 1920s was formidable, though the landscapes, portraits and flower paintings (not included in this exhibition) are pretty wretched things.

In the 1930s he was at odds with the Nazis, 639 examples of his work were confiscated from German museums as degenerate, and in 1938 he shot himself.

In the context of German Expressionism Kirchner is a significant figure, but I am not sure that he should be promoted as head and shoulders above all others in the movement, or even as first among equals. His achievement seems no match for Max Beckmann, four years his junior, whose work was recently exhibited at Tate Modern, no match for his immediate contemporary Franz Marc, who has some claim to be leader of The Blue Riders, and his subsequent influence was no match for Kandinsky's.

There can be little doubt that his figures are less convincing in their emotional content and expression than those of Mueller, Heckel and Schmidt-Rottluf; never did he come anywhere near the emotional power of Munch. Neither Beckmann nor Munch was an Expressionist, but they, with Dix and Grosz, outdid The Bridge and Blue Rider groups in almost everything that they attempted.

If this seems curmudgeonly, that is not my intention; this is a serious and illuminating exhibition, designed for those who are seriously interested in the history of art and who are prepared to be sceptical even when confronted with a great weight of opinion.

German Expressionism is more than the sum of its parts, a phenomenon in which the groups were greater than the individuals; the individuals are to some extent diminished by being separated.

Were the Academy ever to give us a major exhibition of German Expressionism as a whole, with all its ramifications - reaching to Klee, Kokoschka and young Egon Schiele, for example - Kirchner's paintings and sculptures would be woven into a far richer fabric, one thread of a dense warp and weft.

Then, though it might still defy definition, we would at least understand what we mean when we use the term German Expressionism.