THE distinctive sounds of dockers' work songs once dominated Shanghai's port when boats were unloaded using manual labor. Tan Weiyun hears from a local troupe who continue to carry the tradition.

Performers dressed in ragged clothes and a hand towel on their shoulders are humming, groaning, trolling or chanting songs that contain simple but powerful lyrics.

They are singing the maotou haozi or dockers' work songs, a style of singing accompanied by strong beats, once popular among the dockers and coolies who toiled on the docks along the Huangpu River in the late 19th century.

Through grieving and desperate lyrics, listeners can get an idea of the hard life of dock workers more than 100 years ago.

Today, senior folk artists from the Tangqiao Folk Arts Troupe in the Pudong New Area revive the days of yore on the docks by bringing this 100-year-old grassroots art form to the public stage.

"It's a record of the history, which should be kept and carried forward," says Wang Xibao, the art troupe's deputy director who also initiated the preservation project of the dockers' work songs in 2005.

Now it has been listed as one of the country's intangible cultural heritages.

Located by the mouth of the Yangtze River and the East China Sea, Shanghai was opened as a trading port in 1843, linking the world's big cities and becoming one of the country's shipping centers.

Before 1949, Shanghai port had a 10.7-kilometer-long coastline for the public docks, boasting a total of 79 berths, among which 26 could handle more than 10,000 tons of throughput.

However, the under-developed dock-loading facilities couldn't keep up with the quick expansion of the port. So the loading and hauling of the heavy, bulk goods had to be done by the backs, shoulders and hands of dock workers.

In order to haul heavy goods, dockers had to work in coordination with each other - as one and at the same pace. The work songs with strong beats, easy lyrics and simple rhythms, were then created during the toil.

They made haulers work in sync and also helped relieve work pressure.

"The work songs were very important because they could efficiently reduce the risks of injuries and deaths when moving the extremely heavy goods," Wang says. "They sing out the pains and the bitterness of coolies."

As there were a number of docks along either side of the Huangpu River, many people - local farmers, fishermen and boatmen from other coastal provinces - soon gathered at the Shanghai port and made a living from hauling on the docks.

They worked in "colonies" - groups of Jiangsu, Zhejiang, Hubei, Shandong and Shanghai natives. Each group's songs were unique due to the various dialects and accents.

"The moment the carrying pole was put on the shoulder, the song came out naturally," Wang says.

Every dock worker had various tools for hauling, such as a shoulder pole, a hand towel, grass shoes, straw ropes and bamboo baskets.

During that time no one would hire a hauler who couldn't sing the work songs.

Most haulers were seasonal workers, who flowed from this dock to another, so the songs were mainly carried forward by group members who came from the same place - father to son, elder brother to the younger, one townee to another.

"No one was willing to work with you if you couldn't sing the work songs," recalls 80-year-old Cheng Nianwan, who worked as a boatman on the port in 1949. Born with a good voice, Cheng was the leading singer on the dock. It is said that people in the Puxi area could hear his resounding voice across the Huangpu River when he was singing on the shore of Pudong.

Lyrics were quite simple, easy to remember and sing: "A pole is carried by us; heavy life loads fall on our shoulders; marching in sync and acting like one man, we support ourselves by hard work." For the overseers, there was another version: "To the east and past the bridge, everybody hold on and the destination is just a few steps away."

Different goods, hauling routes and moving methods generated different work songs. There were songs for one man, two men, four men, eight men, 16 men and even 32 men, songs for goods carried on the shoulders, backs, with the poles and by the machines.

There were also songs from the overseers, who were responsible for assigning the jobs and setting up the hauling routes to various warehouses or ships and to avoid collision among different haulers and teams.

"Ningbo people were the overseers, probably because they were smarter and better at socializing," says 69-year-old work song performer Chen Yusheng. He can sing a wide variety of work songs with different accents and dialects. Chen has sung work songs for almost a decade. He isn't a docker; he sings because he likes it.

Songs for goods on shoulders were in a short form, slow tone and a low pitch because the goods were usually heavy.

Songs for goods carried by the shoulder pole were often with a quick tempo, light melody, cheerful rhythm and ascending voice because the goods were not heavy.

But if the goods were too big and heavy to be carried by one man, they required teamwork, which needed a leader to direct the song.

The more haulers, the more they depended on the songs to work in sync.

The leader, who usually stood at the rear of the team, sang first to set the tone for the song; then the haulers around the leader echoed him, which would be joined by the workers in the front part of the team.

They marched forward together, while the front and the back echoed with each other until they reached their destination.

Tempo was alternated between slow and quick, which also required the coordinated change of steps and pace speed.

Today, most dock workers have passed away.

With the modernization of the Shanghai port, they are no long needed and the work songs have completely left the stage of history.

"Unlike other folk arts and skills which can be kept by various forms such as carving or story-telling, dockers' work songs are very difficult to be preserved because no one sings any more," Wang says.

The only way to carry it forward is to bring them onto the stage.

The Tangqiao Folk Art Troupe established the team of dockers' work song, made up of elderly singers.

During the past six years, the team has given performances throughout the Yangtze River Delta region; they have won a number of awards and made great contribution to the preservation project.

"It's the history of Shanghai, which records the city's bygone days. When we are speeding forward, we shouldn't forget where we started from," Wang says.