Ahn Sook-Sun, for South Koreans a Living Human Treasure, makes her theatrical entrance borne aloft like a little doll by two assistants who plant her centre-stage with reverential care. At first she cuts a frail figure in her voluminous dress. Her voice – something between a gurgle and a yodel – seems to come from far away, but she’s soon weaving a spell with a story about two brothers. The elder is an anarchic ne’er-do-well who kicks disabled people and pisses in the communal wine; the younger is so caring that he mends a swallow’s broken leg; virtue is eventually rewarded, and a message of brotherly love affirmed.

Accompanied by a drummer who also acts as her narrative feed, Ahn evokes not only the brothers but also their entire village: the stiff little doll becomes a commanding figure. Her gestures are grave and stately, and she uses her fan to suggest everything from feminine modesty to murderous aggression. In her driving, rhythmic chant one senses a kinship with Kyrgyz recitations of the Manas epic; the repressed passion in her voice is reminiscent of the sound-world of Japanese Noh. She may be telling a Confucian morality tale, but she punctuates it with poker-faced asides which have her audience in stitches: much of her story is pure slapstick. In the course of her first gruelling hour, she takes just one sip of water: for a septuagenarian grandmother, Ahn’s stamina and authority are remarkable.

This is p’ansori, Korea’s home-grown answer to opera, and a form of epic story-telling which goes back four centuries; its name conflates the words for ‘meeting place’ and ‘song’, and its original purpose was social commentary, morally improving and politically satirical. It was initially a quasi-shamanic art practised by men, with women coming into the frame in the late nineteenth century. In 1964 it was declared an Intangible Cultural Property, and in 2003 UNESCO added it to its list of protected musics. Ahn is one of her country’s leading exponents of this art, and after her performance she gives me a brief sketch of her credo and career.