Like an eager if overage pupil, China has embarked on an ironic pilgrimage to learn from its ancient cultural offspring and once bitter enemy - Japan.

Communist Party leaders in Peking tell visitors they plan to follow the example of the 1868 Meiji restoration and the Japanese economic miracle.Chinese Vice Premier Teng Hsiao-ping just visited Japan with the announced intention to "learn from the . . . Japanese people." He returned to Peking yesterday.

A Cabinet-level delegation is following him to explore "the secrets of the high-growth Japanese economy."

Although there is much in garish, capitalistic Tokyo that the Chinese do not want to copy, they have signaled that of all the world's major industrial powers, Japan is now the favorite model for China's 900 million people. Since the two countries normalized relations in 1972, an estimated 120,000 Japanese have visited China while perhaps 12,000 Chinese have seen Japan, a depth of contact China now has with probably no other country.

In Japan the Chinese find lessons in efficiency and enterprise not so tainted by the rugged individualism they find so distasteful in the West. Japan suggests a way to build modern factories with losing too much of traditional arts and a way to borrow from the West without being controlled by it. Japan offers economic vitality without immense income differences or social schisms. It insists on a respect for elderly leaders that sits well with China's current gerontocracy.

"The Chinese see us Japanese, like themselves, as not being explorers in modern technology," said one Japanese diplomat. "They are interested then in studying how we adapted what we found in the West so quickly."

It is to both the Japanese and Chinese a most interesting turnabout, for if the latest anthropological theories are to be believed, the Japanese of today are nothing more than the offspring of Chinese colonists who arrived on the island about 200 B.C. Those comparatively recent colonists - by Asian standards - supplanted an ancient Japanese race that survives now as the primitive Ainu tribe.

To this day the Japanese use the Chinese written language and have cultural traditions extensively borrowed from their hugh neighbor to the west.

But when both countries were hit by the onslaught of superior European technology in the 18th and 19th centuries, the Japanese found a way to modernize quickly under the enlightened leadership of the Meiji emperor. At the same time the Chinese empire resisted the modernizers and the ancient nation crumbled into factionalism and revolution.

China reunified under a Communist government in 1949, but has been handicapped by continuing political disputes and has not even approached the progress the Japanese have made in rebuilding since World War II. When a new government took over in China in 1976 after the death of Chairman Mao Tse-tung, analysis wondered how much it would change Mao's policy of economic self-reliance and what foreign examples it might follow.

The most prophetic answer came in an unusually detailed wall poster that appeared on a busy street in Canton on Jan. 23, 1977. With language and authority that seemed to indicate inspiration from very high in the Communist Party, the poster pronounced open envy of the Japanese.

"In 1957, Japan produced about 10 million tons of steel, approximately the same amount as China," the poster said, "but in 1972, Japan's steel production was more than 100 million tons while ours was only 20 million tons."

It said that despite japan's great losses in World War II it managed to produce almost twice as many motor vehicles as Chinese and has a 60 per cent higher yield per acre in rice farming.

"Does this mean," the poster asked, "that the Chinese people are less intelligent than the Japanese, that we are less diligent?"

No, it concluded, but many major changes in the Chinese economic system were necessary. It listed a series of measures that in the 21 months since have become officially enshrined as China's new economic program factory-worker wage increases, bonuses, strict cost accounting, more consumer goods, higher incomes for peasants, and rapid introduction of foreign technology.

In all this, speed is of primary importance. The Chinese slogan has come to be: modernization by the year 200.

The independent Hong Kong newspaper Ming Pao reported last week that recent visitors to peking asked Chinese officials if this were not too fast. The Chinese replied by citing the Meiji restoration.

"They said the reform turned feudalist and backward Japan into a modernized nation-state in a quarter of a century," Ming Pao reported.