In the 1980s, Chang, who then worked at Tongzhou District Cultural Center in Beijing, received tasks to compile the ballads. He started visiting old-timers to record their singing, and that is when he discovered Zhao Qingfu, a veteran sailor with exceptional chantey skills.

In 2006, Tongzhou's canal chanteys were listed as a city-level intangible cultural heritage and Zhao, then 75, became its inheritor. "The one who sings chanteys plays a leading role in a boat," says 65-year-old Zhao Yiqiang, the son of Zhao Qingfu and the sole heir of this heritage after his father's death in 2018.

"The rhythmic songs helped the sailors row in sync, and maintain both speed and direction. In other words, the person leading the chantey chorus influenced and unified the pace of work," Zhao Yiqiang explains.

"The lead chantey singer knew how the boat functioned, was very familiar with the waterway and even had knowledge of local customs of the places the vessel passed by," he adds.

In the olden days, the cargo boats transported large quantities of tea, porcelain items and silk from south to north China, and helped ferry medicines, fur and artifacts from north to south.

There was at least one chantey for every boat function. For example, there was a song for reminding sailors to weigh anchor and yet two others for embarking and disembarking cargo. Chang has organized these chanteys into 10 groups and compiled a total of 22.

Chanteys were customary along the entire length of the Grand Canal in the past. Efforts have also been made to save them in Wucheng county, Shandong province.

Wucheng's canal chanteys were listed as provincial-level intangible cultural heritage after Chen Zhongkui, who worked with the local cultural authority, visited sailor Liang Yonghe in 2006. Chen spent more than a year interviewing Liang, then 85, about his family and fellow sailors. Chen recorded Liang's singing and turned it into scores.

"When I was about 10, I lived with my grandmother in a village near the canal. Listening to the chanteys was my favorite pastime," says Chen, 82, now the sole inheritor of Wucheng's canal chanteys.