Elliott says the ties that bind Tokyo and Berlin stem from a similar history. 'They're both newly invented cities.'

Tokyo dispatched its envoys across the world after it reinvented itself as Japan's capital in 1868 during the Meiji Restoration, just as Berlin became the capital of the new German empire in 1871.

The results of this first encounter are woven through Japan's artistic, architectural, political and educational landscape like strands of cultural DNA - as anyone who has seen the German-inspired black uniforms of Japanese schoolboys might acknowledge. Among other examples, the exhibition highlights two Berlin architects who designed Tokyo's original Ministry of Justice building (1887).

But Tokyo-Berlin also highlights what Elliott calls the hidden history of Tokyo's influence on the German city.

'In terms of knowledge and skills, Germany, of course, had a big impact,' he says. 'But what goes the other way is a way of looking at the world, based partly on exoticism and difference.'

He cites the impact of kabuki on theatre and cinema - 'the shadows, use of masks and stylised acting, which goes very much into expressionist cinema and the work of people like [Marxist dramatist Bertolt] Brecht'.

And he says German architects were in awe of 'the rectilinear simplicity' of Japanese constructions. 'The relationship between the inside and outside, and with nature - this is Bruno Taut, Walter Gropius, Ludwig Mies van der Rohe. That whole generation was influenced by this.'

Tracing the contours of the bilateral cultural relationship from those early pioneers through to the present hasn't been easy - nor have the results pleased everyone. The Japan Times' art critic called the exhibition 'a dog's dinner'.

Like others, he questioned the wisdom of trying to squeeze such a riot of styles and art forms - including oil painting, photography, video installation and murals - from 20th-century cultural history into a single floor of Mori Tower.

It doesn't help that, with the exception of German expressionism, most of the last century's art movements, such as impressionism, cubism, futurism and surrealism, originated elsewhere.

Still, the exhibition's sheer eclecticism is dazzling - from the jarring juxtaposition of tradition and modernity during Japan's early encounters with the west (evoked in the likes of Kinshu Hahakabe's Mitsukoshi Department Store Poster) to the savage Dadaist caricatures of George Grosz, the playful pop art of Yokoo Tadanori, and the big abstract murals of contemporary Berlin artists such as Katharina Grosse.

'It's looking at one of the big stories about the encounter of Asia and Europe,' Elliott says. 'It's putting it through the prism of two cities, with all the good and the bad things that come out of this.'

What the show lacks in coherence in its 11 themed galleries, it more than makes up for in exuberance. And although the connections aren't always obvious, it's fascinating to see the way countless cultural strands have cross-fertilised each side: Ernst Ludwig Kirchner's expressionist portrait of a geisha, for example; and the influence of Japanese minimalism and attention to detail on the Bauhaus movement; or the way expressionism, Dada and surrealism helped pollinate the short-lived experimental political and cultural flowering of 1920s Tokyo, before militarism and fascism snuffed it out.

Inevitably, the section likely to draw most attention is The Dark Years 1931-1945, which also happens to be the smallest part of the exhibit. But Elliott denies any attempt to gloss over the era of the German-Japan Axis.

'Well, the first piece is of a guy being tortured to death [Tsuda Seifu's The Victim]! It's a matter of space as much as anything else,' he says. 'We've tried to show resistance art as well as official art. In Japan, you had this militant nationalism that most of the country, including the intelligentsia, gets swept up in, but some of the art is very high quality. But the official art of Germany wasn't very good.'

The post-war period is one of the exhibition's most inspiring, with some remarkable photography of the rebirth of two cities that had been reduced to rubble.

Tadahiko Hayashi's demobilised soldiers in Dark Days after the War captures the optimism and vitality of the immediate post-war years, and Shigeichi Nagano's The Dream Age is a photographic distillation of the male corporate world that led to Japan's economic boom. The section on the thriving Berlin art scene - yet another narrative of renewal and regeneration - will be fresh and new to many.

The unenviable job of putting a full stop to all this was handed to Grosse, whose huge mural covers the final wall of the exhibition. 'I don't like to think of summing up,' she says. 'This is a conceptual show with a lot of historical background, and it's also divided into sections, with painting on walls and so on. My work is not all working with that set of rules. It doesn't have clear boundaries or precisely tell you what is being dealt with. My art is about uninhibited thinking in a public space, free movement on a wall.'

Still, she acknowledges that, at some point, 'we artists have been influenced by the art in the preceding rooms. We have to confront or deal with it in some way'.

Her approach is to retreat into the abstract. 'I'm not interested in representative work because it's too limiting and defining. I'm interested in the process of flux and transformation.'

It seems a fitting point to end a cultural exploration of two cities that have transformed so remarkably over the past 120 years - certainly more appropriate than the oddly jarring foreword to the exhibition by Tokyo's governor, Shintaro Ishihara. The xenophobic politician praises international culture and art, which is, perhaps, like George W. Bush writing a poem about peace and goodwill. But then, history, as this exhibition shows, has a way of making nasty things obsolete.

Tokyo-Berlin/Berlin-Tokyo, Mori Art Museum, 53/F Mori Tower, Roppongi Hills, 1,500 yen (adults), 1,000 yen (students), 500 yen (children). Ends May 7