ARCHITECTS Renzo Piano and Noriaki Okabe had never built an airport when they sat down in the late 1980s to design one for a man-made island in the bay off Osaka, Japan.
But, says Mr. Okabe, ''We knew airports -- as passengers.'' The way he speaks English, with traces of Japanese, French, and Italian, underscores the fact that he is well-traveled.
''There's something quite wrong in airports,'' he adds. ''You lose yourself very easily.'' So he and Mr. Piano, best known for his work in co-designing the Pompidou Centre in Paris with British architect Richard Rogers, set out to create a terminal in which you cannot lose yourself.
In their design for Kansai International Airport, they may very well have achieved this end, although there will always be people who will find ways to get lost in airports.
Even amid the anxiety produced by travel and too many fellow travelers, Kansai offers moments that are transporting in ways that have nothing to do with airplanes.
Airports can be difficult places. People are leaving the earth for the sky, very often one country for another, and sometimes one phase of life for a new one. Kansai International's terminal and concourse can soften these edgy transitions, not because it's well organized but because it offers the occasional architectural thrill.
Kansai's departing passengers have the greatest opportunity to appreciate the architecture. People checking in at the international departures area do so under a graceful, swooping ceiling that is the terminal's best feature.
Piano is known for his embrace of structural materials, and the trusses that support the arched ceiling are in no way hidden. It's an asymmetrical arch that in cross-section looks like an undulating wing, but Okabe says they had nothing so definite in mind. Instead they sought to convey grace and fluidity, he explains.
In between each of the trusses, which rise to a height of almost 60 feet over the departures area, is a sail-like piece of stretched canvas that reflects light and directs streams of air from ventilation blowers. The ceiling is thus as weightless as it looks: It carries no lighting fixtures, air ducts, or maintenance platforms.
The designers erred when they installed a distracting series of metal and cloth mobiles that hang just below the canvas sails; the colors of the artworks clash with similar hues elsewhere in the terminal. The effect is to mar the purity of the ceiling's curves.
All passengers, domestic and international, will wait at gates set along a mile-long concourse that defines the linear character of the airport.
The concourse's unending windows, overlooking airplanes and the runway, are curved in a way that suggests a spinnaker sail filled with wind. (Even arriving passengers walk through this space on their way to baggage claim or an exit.)
Kansai International does for the straight line what Paris's Charles De Gaulle airport does for the circle. The main terminal at Charles De Gaulle is like a stack of tires, with glass-enclosed moving sidewalks traversing the hollow core. The gates are located in circular, outlying pods called satellites.
The layout for Kansai, oddly enough, was created by Aeroports de Paris, the firm that designed Charles de Gaulle. Here again, ADP used the stacked-terminal concept, with arrival and departure areas located on different floors and connected by escalators and elevators. But Kansai's four-story terminal is rectangular, and connects to the incredibly straight, incredibly long gate concourse.
Domestic passengers whose gates are located where the terminal connects to the concourse are fortunate: It's an admirably short trip from the train station. A shuttle on rails carries passengers whose planes are at outlying gates.
The airport is the world's most expensive, and its economic viability is somewhat in doubt. The $15-billion facility has been two decades in the planning, and it will take at least another two for the public-private consortium that owns Kansai to pay off the huge debts it has incurred. It is a product of overly optimistic thinking about Japan's economic potential, and the owners have had to scale back their plans, settling for a single runway.
Even before the opening on Sept. 4, there were calls for the Japanese government to step in with additional money for the construction of two more runways.
The terminal and the gate concourse were the only elements of the project designed by the Renzo Piano Building Workshop, but the island on which it sits is no less a marvel. To create the 1,300 acres of reclaimed land, engineers had to move 234 million cubic yards of earth and sand -- enough to build the Great Pyramid at Giza 13 times.
New high-speed trains operated by two different companies are plying the two-mile bridge to the mainland and nearby Osaka. One of them, called the Rapi:t but pronounced ''rapido'' in Japanese, is pure whimsy on rails, something you might find in an amusement park. The outside, painted a deep blue, looks like some sort of mechanical worm. The inside is Art Deco redux: faux birds-eye maple paneling and gray leopard-skin upholstery. Only in Japan.
Many architecture critics have already praised Kansai's design, but the really good news is that the pilots like it. The airport is covered in a matte-finish steel that appears glare-free when seen through tinted glass.
And because Kansai International lies on its ''very tight, small, expensive island,'' as Okabe puts it, the landing approach offers few distractions.