It took 3,000-year-old principles to solve a thoroughly modern puzzle that Montgomery County planners have spent seven years and countless computer hours trying to untangle.

The problem was coming up with a comprehensive policy to deal with growth in the affluent, 500-square-mile suburb.

Simply put, the solution now porposed rests on a modification of the ancient Chinese concepts of yin and yang, which represent the two-fold nature of the world, such as darkness and light, male and female.

While no disciple of Confucius would have used such notions to keep shopping centers out of overdeveloped areas, Montgomery planners thought it was the perfect way to simplify "a very, very complex problem," according to Jeff Zyontz, one of the plan's authors.

"King Tut is coming back too," joked Zyontz, who helped to write the county planning board's Comprehensive Staging Plan, which would balance public and private development in the same harmony and wholeness with which yin complements yang.

The planners thought the metaphor might well describe the best way to manage a world in which private developers build approximately 3,000 housing units a year, which public officials try to serve with $340 million a year in new sewer routes, improved roads and other services.

"Yin and yang suggest the duality private development and public facilites is clear, the specifics might as well have been written in Chinese.

Last October, when the plan was first proposed, County Council member Rose Crenca suggested the planner come back with "the Sesame Street version."

The 150-page document, with a flotilla of phrases such as "modal split," "traffic shed," "policy threshhold" and other planners' jargon, left many readers bewildered.

Among the developers who understood the plan, there was alarm that it might further restrict growth in some areas. On the other hand, residents who fathomed it were worried that development could be increased in other areas of the county.

Tustian rechristened yin "CIP" for the county's blueprint of capital improvements, and yang "CSP" for the comprehensive staging plan.

Together, the two principles "establish a rhythm of government action," Tustian said. "One year we will focus on public investments, the next on regulation of private growth."

The plan proposes that the county consider capital-improvement projects every other year instead of yearly, and that in off years, lawmakers scrutinize the growth staging plan instead. The plan would amend present ordinances to allow the approval of subdivisions and other projects to be linked more directly with traffic congestion in various parts of Montgomery.

In some areas, planners say, the public and private sectors have fallen out of synchronization. In Olney, for example, population growth and housing development have outstripped the area's public facilities.

Public facilities haven't meshed with private development in the Gaithersburg area either. Montgomery Village is served by a small library meant for pre-boom Gaithersburg, and the area's main aretery, Rte. 355, is yet to be widened.

While the general aim to balance and repetition that goes through all nature," said Planning Director Richard Tustian who was searching for a symbol that depicted "the creative tension" between the public and private sectors.

"One of the problems," said Thomas Stone, special assistant to the county executive, "is that we just don't know yet what the effect of this plan will be."

The proposal still has to be adopted by the County Council, whose members are currently reviewing the "Sesame Street version." The council is scheduled to discuss the plan in its latest form on Feb. 26.

"The writing was perhaps too technical," said Pat Plunkett of the planning board's community relations section. "That was pretty well evidenced by the reaction. Generally we try to put plans in plain English and have an appendix at the back."

Part of the problem, planners say, was that they were breaking new ground.

"No one has tried this method of staging based on area-wide transportation," Zyontz said. "There is no established jargon. We had developed concepts for which there were no phrases."

Complete with glossary and shorn of much of the technical detail, Montgomery County's plan to bring harmony to the expanding suburbs was unveiled last month. The plan was discussed recently by a 25-member panel described as "professional citizens," where it was well received.

"It's much more comprehensible," said civic leader Elvera Berson.

But she warned that the staging plan could undermine earlier county policy.

"One wonders what the effect of this will be on the general plan (adopted in 1969)," she said. "The reason people like to live in Montgomery County is that it's so well planned."