Slide Show

A steel beam is to be hoisted 977 feet to the top of 4 World Trade Center on Monday, ceremonially signifying the completion of its structural framework.

Building Blocks How the city looks and feels — and why it got that way.

Wait a minute. Four World Trade Center?

Yes, 4 World Trade Center: the biggest skyscraper New Yorkers have never heard of. That’s not only because a much bigger companion, 1 World Trade Center, has claimed the city’s attention. It is because the architects, Maki and Associates of Tokyo, have deliberately designed their tower to be understated and deferential. They are, in other words, not disappointed by a lack of buzz.

“We like the idea of the building dematerializing,” said Osamu Sassa, the project architect for the Maki firm. It is headed by Fumihiko Maki, 83, who won the prestigious Pritzker Architecture Prize in 1993, but has been little known in this country until recently.

Don Hogan Charles/The New York Times

“A lot of inherently good qualities of design take time to appreciate,” Mr. Sassa said. “Subtlety extends one’s appreciation.”

In his design for 4 World Trade Center, Mr. Maki embraced the idea that an office tower at ground zero ought to be a respectful backdrop to the National September 11 Memorial. Because of the modesty and reticence of the building’s design, it was easy to overlook it in 2006 when the it was unveiled by Silverstein Properties alongside those of the far more expressive 2 and 3 World Trade Center, by Norman Foster and Richard Rogers.

At the small scale of models and renderings, 4 World Trade Center didn’t turn many heads. It looked like a silvery extrusion of a trapezoid atop a parallelogram. But as its aesthetic restraint has assumed full scale, it has taken on a dignified monumentality.

That is, when you can see it at all. From some angles, at certain times of day, 4 World Trade Center almost disappears from the downtown skyline. That’s quite a feat for a structure that will be the sixth tallest building in New York on completion next year.

To achieve this effect, the Maki firm designed an especially sheer curtain wall over the steel framework. Glass facades often look cheap because developers will pay only for windows so thin that they bow slightly, creating a quilted effect. The thicker the glass, the flatter the plane of the facade. “It’s not absolutely perfect,” Mr. Sassa said candidly about the curtain wall at 4 World Trade Center, “but I think we’ve achieved something of high quality.”

Even in its raw form, the building shows many refined touches. Mechanical louvers on the lower floors, for instance, are arranged as thin vertical slits, an aesthetic gesture that took a lot of complicated engineering to achieve. There are no louvers at all on the west facade, overlooking the memorial. That made the ductwork even more tortuous.

David W. Dunlap/The New York Times

“This is a special place with a sacred meaning,” Mr. Sassa said, “and we felt we had to be respectful.” The office lobby of 4 World Trade Center also faces the memorial and reflects it at the same time, in a 47-foot-high wall of Swedish black granite that was finished in Carrara, Italy. The Church Street side of the tower will be a much livelier transit hall and shopping center, in keeping with the commercial surroundings.

Silverstein already has two large office tenants, the city and the Port Authority of New York and New Jersey, accounting for just over half of the building’s 2.3 million square feet of space. Each tenant is expected to occupy 15 floors in the 72-story tower. The construction manager is Tishman Construction, which built the original World Trade Center. The structural engineers, Leslie E. Robertson Associates, were also involved in the first twin towers. The $1.67 billion cost of 4 World Trade Center is being met through Liberty Bond financing and insurance proceeds.

The Japanese architects insisted on a level of detail and near-perfection that frequently perplexed and frustrated their American counterparts. But not all of their many subtle touches were purely in the interest of aesthetic clarity.

For example, deep notches were created in the two broad angles of the tower’s parallelogram shape to help define the edges of the facade. “The added benefit,” Mr. Sassa said with a smile, “was that it increased the number of corner offices.”