Diplomatic community.

In their first American building, Heikkinen-Komonen have drawn on the northern lights and the mystical forest-dwelling soul of their homeland to build the US political capital's best building in 50 years.

If architecture is less about space than about time, as Mikko Heikkinen contends, it is intriguing to consider the new Finnish Embassy that he and Markku Komonen have built in Washington. Even without addressing the philosophical questions posed by the Helsinki architects, any plenipotentiary work of art from a country with Finland's reputation for outstandingly good design is bound to arrive with incredibly high expectations.

Washington is hardly known for leadership in the arts -- it doesn't even rank among the more important cities architecturally in the United States. Nevertheless, Washington is the political centre of the world and is an appropriate stage for Heikkinen and Komonen's American debut.

Readers of The Architectural Review are familiar with the work of the young Finns, but they are virtually unknown in the US. Heikkinen and Komonen have been in practice for 20 years and have won competitions, prizes, and good press in Europe for such handsome Modernist creations as a dumb-but-cerebral-box airport astride the Arctic Circle in Lapland, the elegant Kahn-like geometries of a rescue school in Kuopio, and the witty and provocative European Film College in Ebeltoft, Denmark. The Washington embassy may be their best building yet. (Project, AR March 1993).

Part of embassy row on Massachusetts Avenue, Heikkinen and Komonen's misleadingly simple cube is unlike any of its sometimes trite and bombastic neighbours. Opposite the Vice President's house, the new embassy occupies a small wooded lot that slopes steeply down to Rock Creek Park.

By respectfully inserting their building into the forest the architects have exploited the trees to make a statement about Finland's symbiotic relationship with nature. As with Aalto's Saynatsalo, one senses that the trees are more important than the building -- Finland is currently revising its forestry laws to incorporate the 'ethical duty to preserve the soul of trees'. Only three existing trees were lost in the building's construction and more have been planted.

On the embassy's public front there is not a column or a piece of travertine: the main facade is to be a clematis and rose-covered bronze trellis. The chancery's walls of glass and green granite self-effacingly reflect the foliage around them. The understated box is a metaphor for the outwardly reserved Finn, a sophisticated and urbane container for a mystical forest-dweller's soul.

Between the trellis gate and the street is a granite forecourt with a curved ramp leading to an underground garage (all parking for the staff of 50 had to be on site). Lights are innocuously embedded in the granite, but their pattern is part of a larger iconographic scheme revealed farther on.

Before reaching the trees, the embassy interior provides a wonderful sensual experience. The opening to the inside is a heavy, patinated bronze door with narrow horizontal slits of glass in it, almost a minimalist sculpture by, say, Donald Judd. This exquisite entrance of human scale and not intimidating; the single brass grab bar fits the hand comfortably.

The door typifies the usual Finnish attention to detail -- the delight in feasting the eyes and reassuring the hands that we expect of the best of Finnish architecture. In fact, just about everything in the $10 million embassy feels right, from the Charles Eames chairs and Heikkinen and Komonen's grey-stained plywood desks to the unobtrusive yet aesthetically pleasing security system.

Inside, the large public space that forms the embassy's core is reached by a dramatic downward curving staircase. The stairs are light maple and the railings are grey steel with tension wires and exposed turnbuckles, a Heikkinen and Komonen trademark.

Echoing the stairs is a curved light bar featuring exposed halogen bulbs (the tiny ones, as used in a slide projector); when lighted, this chandelier sparkles like a row of distant stars. The same little but very bright bulbs illuminate the ceiling where they are hung, totally naked, with wiring, clips, and screws forming a Constructivist composition.

Also launching from the entrance level, but upward, is a two-storey circular staircase. Constructed only of maple treads and steel framing, this simple device dramatically spins to the offices above with a Baroque energy and Miesian elegance.

Beneath this giant corkscrew and at the bottom of the main staircase is Finland Hall, an all-purpose space riven by a 60-foot-high 'Grand Canyon', which brings daylight into the centre of the building and also provides visual excitement. The larger half of this hall, its 18-foot ceiling supported by six white concrete columns (metaphorical birch trees?), is defined by a seamless glass wall that overlooks the woods at the rear of the embassy.

The appeal of nature through the dissolving wall is strong, but the first hall has an equally powerful pull. For, in addition to the flying staircases and flickering stars, there are two copper-sheathed (yes, copper-sheathed) conference rooms suspended in the space above, plus flanking service towers plated with sandblasted stainless steel. The combination of materials, all the wires and cables, and the gently colliding geometrical shapes not only works, but is breathtaking. The entire space is Piranesian -- half factory, half ocean liner, part Garbo, part Isambard Kingdom Brunel.

The nineteenth-century industrial ambience is reinforced by a modular grid that may in fact have much earlier roots, such as a tatami system. The offices, with their glass block walls, narrow strips of windows, and strong contrasting outlines have an especially Japanese look about them (both Markku Komonen and Mikko Heikkinen studied in Japan). It is not the appearance but the spirit of the traditional Japanese house, with its rigidly prescribed constructional units, that comes to mind here: when the forms are so simple, the proportions, materials, and siting assume a critical importance.

Like Japanese architecture at its best, the embassy is a synthesis of the traditional and the contemporary, with deference to nature. The accent, however, is unquestionably Finnish, for Heikkinen and Komonen have created a beautifully proportioned Modernist building that does not neglect the primal, forest-dwelling heart of the Finn.

The architects refer to the embassy as a jewel box, but it might more properly be called a reliquary, one in which the ghosts of Finnishness have been preserved, held in sacred, decorous trust. This is best seen on the north, less public side. Here glass walls embrace the sloping hillside of woods, and there is a blurring of the boundary between inside and outside, the safety of the cave and danger of the darkness. The trees, many over 100ft tall, compete with the reflecting glass and granite box for the limelight.

The architects have continued the modular pattern of lights announced in the entrance courtyard's granite pavement, but since the hillside drops so steeply here, the lights have been installed on skinny poles, some of which are 40ft high. At night, the lights link embassy and woods and become, in Heikkinen's words, 'a trail of Arctic stars'.

The humour and seriousness, practicality and pure magic of the metaphorical northern lights typifies Heikkinen and Komonen's approach to architecture: traditional principles without eclecticism, Modernism infused with Finnish essence.

The Embassy of Finland is a modest, complex, poetic, even Platonic work in a large city not known for subtlety. It may well be the best new building in Washington in the past 50 years.