For more than 20 centuries, bowing (search) was the way Chinese mandarins (search) greeted each other, commoners paid obeisance to their ruler and everyone worshipped their ancestors. China's communist rulers did their best to stamp out the practice, believing it reeked of the hated imperial past.

Now, in an unusual turn amid attempts to stop the SARS (search) virus and with the explicit endorsement of the Communist Party, the bow is making a comeback.

In the northern province of Hebei, which is trying to choke off a spreading outbreak, the party is telling officials to bow instead of shake hands -- a more modern gesture, but one that doctors say also might spread the virus.

Instructions went out this week, said an official at the party's provincial publicity office.

"It's really a suggestion more than an order, but we want to do everything possible to stop the spread of the disease," said the official, reached by telephone in the provincial capital of Shijiazhuang. He refused to give his name.

It isn't a choice the communists make lightly. Even after 24 years of economic and social reforms that have remade China, the ruling party carefully weighs the political symbolism of every word and gesture. And memories of Chinese being forced to bow to foreigners in colonial Shanghai and Japanese invaders during World War II can still prompt a cringe.

It isn't just any style of bow the party is reviving. The official Xinhua News Agency, outlining the new etiquette, described a greeting used by Confucian gentlemen, a class the communists swept away: "a slight bow with hands clasped at head level."

The government's willingness to embrace such a cultural throwback is a sign of just how desperate the times are.

Severe acute respiratory syndrome has killed more than 200 people and infected more than 4,600 on China's mainland. Tens of thousands of people are quarantined. The government has imposed restrictions on travel and in hard-hit Beijing shut down schools, cinemas and other places where the virus might spread.

Densely populated Hebei, which borders Beijing, has reported 146 cases and six deaths. A World Health Organization team is there investigating a recent jump in cases that it says could be a precursor to an outright epidemic.

"People should avoid becoming estranged, but should adopt preventive measures for certain circumstances," Xinhua quoted Bai Keming, the party secretary of Hebei, as saying during an inspection tour of SARS-affected areas.

In imperial China, the bow could be as slight as the nod of a head from one court official to another. Or it could be an all-out "kowtow" -- literally, "knocking the head," when a subject prostrated himself before his ruler and banged his head on the floor.

Even the emperor bowed -- though only to his ancestors at the dynastic shrine and to the spirits at temples.

Chinese court officials demanded foreign diplomats bow to them -- and were furious when the 18th-century British envoy Lord Macartney refused. Later Westerners followed suit, and their refusal became a symbol of foreigners' ability to dictate to China.

The bow has stayed in fashion on Taiwan, the island refuge for China's Nationalists after their 1949 defeat in a civil war on the mainland.

Taiwanese political candidates bow to supporters, sometimes dropping to their knees on election eve to appeal for those last few votes. On inauguration day, the winners bow to voters in thanks. Even many modern young Taiwanese couples bow to their ancestors at the family shrine on their wedding day.

The Chinese territory of Hong Kong also is trying to discourage people from shaking hands, but offers a different alternative. Authorities in the former British colony tell people to say, "Hi."