In this city of monumental memorials, controversies surrounding their designs are nothing new. And yet arguments over Maya Ying Lin's design for the Vietnam Veterans Memorial have a particular poignance.

Principally, this is due to the nature of the war itself. The nation is still seriously divided in its judgments of the wisdom of our involvement in Vietnam and of our military conduct, once in the thick of it. American soldiers who had to fight in Southeast Asia suffered grievously at the time from this national schizophrenia. When they returned home as veterans they found that these psychological wounds had not healed.

In these unusual and trying circumstances, to design a fitting memorial posed an especially difficult challenge. For this reason the veterans who banded together to form the Vietnam Veterans Memorial Fund were wise to sponsor an open competition in search of a design. Sheerly in terms of the level and intensity of response, the competition was a significant success.

But the end result was more astonishing still: a stunningly simple design submitted by a 21-year-old undergraduate student of architecture was unanimously chosen by the jury of architects and sculptors who had sifted through more than 1,400 entries.

Lin's plan for two long walls of black granite meeting at an angle of 132 degrees and slicing into (or emerging from) the gradual incline of the site near the Lincoln Memorial has been called "bizarre," "shameful" and "a black trench that scars the Mall." Others have praised its "extraordinary sense of dignity and nobility" and the "unclassifiable qualities" that make it "so eminently right."

Just how wrong are the naysayers and how amazingly right were the jurors can be seen in an exhibition of the winning design and its chief competitors that opened last week at the Octagon House. Organized by the American Institute of Architects Foundation, the Octagon show includes the second- and third-place entries as well as 15 honorable-mention designs. It spills over into the lobby of the AIA headquarters building where 43 "meritorious" designs are on view.

Publicity has intervened to such an extent that it is impossible to recreate the suspenseful conditions faced by the jurors when they began to whittle away at the mountain of entries last spring at Andrews Air Force Base. Nonetheless, to know that the designs in this exhibition represent the best of the lot, and then to come upon Lin's entry after perusing them, is to share the sense of excitement and discovery the jurors must have felt.

The story is by now well known that Lin, who has since graduated from Yale University, received a "B" in the course for which she originally created the design. Presumably this was because her presentation totally lacks the professional spit and polish evident in most of the other entries. It consists simply of a few rather hasty elevations, site plans, perspective drawings and three simple pastel views. Even its detractors admit, however, that Lin's idea is stunning.

At the opening of the exhibition last week many viewers commented that Lin's words were what won her the day. It may be true. Her written statement avoids jargon and technical detail. It explains, for instance, why the list of names of the dead and still missing Americans engraved into those walls will begin chronologically at the upper right edge of the angle and end at its lower left edge: "Thus the war's beginning and end meet; the war is 'complete,' coming full circle, yet broken by the earth that bounds the angle's open side, and contained within the earth itself."

But what won me to her design was the site plan. The place itself is a wonderful glade at the easternmost end of Constitution Gardens. Lin's long black walls, upon which will be engraved the names of more than 57,000 American dead or still missing, are based upon the simplest, straightest sight lines to the Lincoln Memorial and the Washington Monument. In short, her scheme takes charge of the site in the most direct and disarming way.

Even more than its straightforwardness, the beauty of her idea is its esthetic and emotional balance. There are admirable sides to many of the designs in this show, but none of them so succinctly responds to the competition requirement that "the memorial design should be contemplative and reflective in character."

Indeed, by contrast the rhetorical flair of many of the competing designs seems grossly excessive. One proposes a constant, if soft, bombardment of recorded messages stating the names of dead and missing; another a system of sparkling lights beside each name; yet another allows for "a simple tribute" of placing a single flower in a hole bored into the stone beside each name. None of these ideas, and others, would wear well.

A number of the entries suggested some form of figurative sculpture -- a rifle squad, a gigantic host of soldiers or even a statue of the goddess Athena, protector of the brave. But the problem is that since the death of Henry Shrady, who created the memorable statue of General Grant and its fiery ensemble at the other end of the Mall, we have lost the skill to bring such huge groups to life, be they symbolic or realistic. Or perhaps the problem is deeper: All of the proposed figurative schemes are too specific. They limit the range of possible responses.

Thus, more frequently the designers turned to abstract symbols, vertical plinths or columns in various configurations. If anything, these vertical elements are even more cliche'd than the figurative proposals, albeit in the opposite way: They say very little. Besides, they suffer greatly from comparison with the towering obelisk of the Washington Monument, which in this city really does say the last word about vertical abstractions.

All of the more responsive and imaginative designs, therefore, veered away from outdated rhetoric of any sort. Quite a few beautiful, self-enclosed parks were designed, but even the best of these seem to be too pretty, too relaxing and therefore, in the end, inappropriate. To my mind the closest rival to Lin's design was submitted by Laura Frances David, who proposed that a large dish be burrowed into the ground, with a name engraved upon each of its paving stones.

Even this quiet scheme seems intrusive by comparison, however. In seizing upon the horizontal, Lin got to the heart of the matter. In aligning her earthwork so sharply to the major sight lines of the glade, she emphatically and brilliantly set her non-monumental monument in context. Still, for all of its serene beauty, there is a certain tension in Lin's design.

Those impressive, long black walls, set into the earth, are perfect. They will invite the viewer to walk down the hill. They will demand a response without dictating what it should be. They will insist simply that he reflect in some way upon the nature of the sacrifices made.

The American Institute of Architects presented the young artist with an award at the opening last week. It said, "To Maya Ying Lin . . . she spoke softly where others were wont to shout." That is well put. But she spoke clearly and with a strong voice, as well.