Busan International Film Festival programme director Nam Dong-chul told AFP that Youn's Oscar nomination "acknowledges an extraordinary actress who has pioneered her own path for a very long time".

"I don't think she ever intended to break into the international film scene," he said, "but throughout decades she has developed a fine taste when choosing her projects".

'Scarlet letter'

In a career spanning more than 50 years, Youn has often played provocative and atypical characters who do not conform to the rules of socially conservative Korean society.

Born in 1947 in Kaesong—now in North Korea—she made her film debut in groundbreaking director Kim Ki-young's 1971 Woman of Fire, as the live-in maid to a middle-class household who becomes impregnated by the father of the family. The thriller was a critical and commercial hit, and remains a classic of modern South Korean cinema. But Youn's first heyday came to an abrupt end in 1975, when she married singer Jo Young-nam and the couple moved to the US.

Youn returned to South Korea in 1984. But after divorcing Jo three years later, she battled heavy stigma to resume her acting career to support her two children.

"To be divorced was like having the scarlet letter at the time," Youn told a local magazine in 2009. "There was this thing that dictated women shouldn't make TV appearances so soon after their divorce."

She countered by accepting every role she was offered, however small.

"I worked very hard. I had this mission of somehow feeding my children. I'd say yes even when I was asked to climb 100 stairs."

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'Fiercely competitive waters'

By the 1990s Youn was a regular in TV dramas, often portraying mothers, and later grandmothers.

In 2003, Youn made her film comeback in director Im Sang-soo's A Good Lawyer's Wife, as an unconventional mother-in-law in a dysfunctional family.

She played a cruel and rich heiress betrayed by her husband in Im's 2012 thriller Taste of Money, and an ageing haenyeo—the women of Jeju island who free-dive to collect shellfish—reunited with her long-lost granddaughter in 2016 drama Canola.

Also in 2016, she was praised for her role in E J-yong's drama The Bacchus Lady as an elderly prostitute—a veteran of the brothels set up for US soldiers in the South—who becomes involved in the deaths of former clients.

Youn is "one of the few leading actresses of her generation" to have worked consistently in Korean cinema over the last two decades, said Jason Bechervaise, a professor at Korea Soongsil Cyber University.

She had to navigate, he added, the "fiercely competitive waters" of a film and television industry "largely focused on young and often male talent for leading roles".

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