Wang had ventured from his home in San Francisco to the grasslands of Inner Mongolia on a quest to mine the ancient harmonies of the Middle Kingdom. He had lobbied state authorities and waited months for permission to visit Hajab.
Imprisoned as a traitor in the 1960s, Hajab says he drinks to forget the past. He is 85 now, and his hearing is nearly gone. A lone yellow tooth protrudes from his lower gums, and cataracts have stolen his sight.
Once known as the King of the Grasslands, he rarely sings anymore.
Although it was well before noon, he sipped warm beer from a yellow plastic cup. His mood was dour.
Then two Chinese musicians, one a former student of his, began tuning their Mongolian horse-head fiddles. Hajab grew silent. As the two played the song "Old Bird," his head began moving to the rhythm.
Slowly, he began to sing.
Wang's hands shook with excitement. He glanced at his video camera to make sure he was capturing the moment for posterity.
Wang, 46, is a musical archeologist. For years he has crisscrossed mainland China in search of folk virtuosos, recording impromptu performances on some of the country's 400 ethnic instruments.
He has learned to play two dozen himself. There's the banjo-like ruan, or moon guitar, a four-stringed instrument used in the Beijing Opera. There's the xun, a clay-vessel flute resembling a beehive with finger holes, and the laba trumpet, which mimics bird song. "I see these instruments — mute, beautiful, mysterious — and I have to play them," Wang said. To find the old masters, he has traveled by donkey and bicycle over mountain passes. He has played cultural detective, coaxing information from residents, tracking down musicians wary of disclosing the secrets of their craft.
For everyone, Wang has many questions: How are the instruments played? Can they find an audience in a generation obsessed with electronics?
Back in the United States, through his nonprofit Melody of China, an ensemble of musicians trained at some of China's most prestigious conservatories, Wang stages performances by traditional musicians to give the folk music a broader spotlight.
He performs and lectures around the world on Chinese music — all while struggling to meet deadlines for grant applications to keep his dream alive.
Sometimes he worries that he may be too late. He once tracked down an expert on the four-string sihu in a village near Nanjing and was fascinated by the musician's stories. But before he could return, the man died.
Wang still is searching for the zhui hu, a two-string bass fiddle thought to be extinct.
He reached Hajab in time. On a cool summer morning, the master performed a favorite piece called "A Fine Horse."
"Riding a quick red horse, you should tighten the halter going to a far distance," he sang in his native Inner Mongolian dialect as the two fiddlers accompanied him. "You should persist and be patient."
Hajab explained that during the Cultural Revolution, one of his songs angered the Communists. The lyrics evoked a mountain in bordering Mongolia, which became independent from China in the 1920s.