On March 4, the opening salvo will be fired in a new retailing war in Washington.

On that day, the highly respected Seattle chain Nordstrom Inc. opens its doors in Tysons Corner shopping center -- the first of what promises to be many Nordstrom's stores on the East Coast.

Four months later, the war will intensify when the R.H. Macy Co. opens its long-awaited store at the new Tysons II Galleria shopping center, across Rte. 123 from the Tysons Corner center.

The arrival of these two supermerchants represents a new era in the intensely competitive Washington area retailing market.

Long-established merchants who have been vying for the business of increasingly reluctant shoppers now have to face the new rivals, both of which are well known in the retailing industry for their wide selection and attentive customer service.

What's more, the Macy's and Nordstrom's stores are only the beginning of a long-expected expansion by major national chains into the Washington area, particularly in Northern Virginia, where more shopping malls are being built. Saks Fifth Avenue, Neiman-Marcus and Lord & Taylor have announced plans to open additional stores in the Tysons area.

In addition, Henri Bendel and the French department store Au Printemps are reportedly looking for sites in the area.

Meanwhile, Macy's and Nordstrom's are planning to open more area stores. Both chains are building stores in the Pentagon City shopping mall, which is under construction. Nordstrom's also "has three more deals it is looking at," said Jim Nordstrom, president of the 39-store chain. With a new, $6.8 million distribution center just opened in Prince George's County, "We could open one store a year, at least initially," he said.

The onslaught of these new stores is one more sign of Washington's affluence, where average after-tax household income is significantly higher than that of any other major metropolitan area in the nation.

And with the economy more stable here, thanks to the large percentage of government employees, "every major national retailer wants more of a presence here," said Neal J. Fox, chairman of Garfinckel's and Raleighs.

"This is a fine retail marketplace that is changing for the better," Fox said. "It should grow significantly over the next decade."

For consumers, the increasing number of supermerchants means only good news, retailing experts said. More competition will bring not only a greater variety of goods to the store shelves but also better service and even price wars as retailers vie for shoppers.

"There will be a greater premium for imaginative merchandising, better service and aggressive marketing by the long-established merchants in the area who will have to fight hard for consumer dollars and promote more -- especially in light of the outlook for 1988," when consumers are expected to curb their spending somewhat, said Eliot H. Benson, a financial analyst with Ferris & Co.

Because the bulk of the new stores won't open until after this year, local retailing officials doubt that retailers -- especially those outside the Tysons area -- will feel much of an impact.

Initially, "I don't think all hell will break loose," said Garry Curtis, head of the Greater Washington Board of Trade's retail bureau. "On the other hand, it's the first of reportedly four stores for Nordstrom's and four or more for Macy's, so it's the beginning of a shift in the market."

Ultimately, however, "Macy's and Nordstrom's will provide alternate shopping experiences," said Kenneth M. Gassman Jr., an analyst at Wheat First Securities. "Somebody locally will lose market share -- those who haven't remodeled or upgraded their stores."

To guard against that, most major local chains are redoing their stores, in some cases making radical changes. Bloomingdale's store at Tysons Corner, for instance, is turning basement space into an additional 25,000 square feet of retailing space.

At the same time, several stores, including Woodward & Lothrop Inc. and Bloomingdale's, have revamped their employee-compensation systems, adding commissions and other pay incentives, to encourage sales clerks to provide better customer service.

Of all the chains here, the Hecht Co. appears to have the least to lose, retailing officials said, because it sells more moderately priced merchandise than the newcomers.

Hecht's chairman Warren J. Harris agreed. "We've got a pretty good niche; our price line is below Nordstrom's and Macy's. The real battle is in the upper market -- at Woodies, Garfinckel's, Bloomingdale's. All of this group will be cutting up a piece of the pie a little less."

Even so, Woodies and Garfinckel's officials remain confident of their futures.

Woodies chairman Edwin Hoffman predicted that the new stores will draw more customers to the area, increasing business for everyone.

Garfinckel's Fox said that with a small presence in Tysons, "Why should I be hurt?"

The increasing competition at Tysons, which includes a major renovation of the original Tysons Corner center as well as the opening of the 125-store Tysons II complex, is prompting other malls to upgrade as well. Springfield mall and Fair Oaks mall have completed major additions. Meanwhile, Landmark Center broke ground over the weekend for a $135 million renovation project that will turn the single-level mall into a three-story facility by 1990.

Department stores are not the only local retailers that will be in for major changes in 1988.

This year, consumers also may begin seeing radical differences in local drugstore chains, as a result of major management changes at the three chains last year.

Peoples Drug Stores Inc. has been remodeling its stores and stocking them with more health and cosmetic products instead of general goods -- such as trash cans -- in the wake of the dismissal a year ago of Peoples Chairman Sheldon W. Fantle by the chain's parent company, Imasco Ltd.

Meanwhile, Fantle took over financially troubled Dart Drug Store Inc. and is drawing up plans to redo the chain's 80 stores. At the same time, Rite-Aid is remodeling the Gray Drug Fair stores it bought last year.

Competing against these drugstores with increasing intensity are the major local supermarket chains, Giant Food Inc. and Safeway Stores Inc. -- making the drugstores' turnaround efforts all the more challenging.

At the same time, Giant continues to widen its lead over other area supermarkets as it opens new stores and remodels old ones. Safeway, still struggling to overcome the belt-tightening caused by the 1986 management buyout, has been pruning its lineup of stores, causing its market share to decline.