A Vietnamese website, which only works when users correctly answer a quiz about disputed islands in the South China Sea, has infuriated scores of television fans in China desperate to catch the latest episode of a popular Chinese period drama.

The drama — "The Story of Yanxi Palace" — has attracted a huge following in China for its colorful depiction of Qing Dynasty-era politics and the tale of a brave and plucky young concubine who outsmarts her rivals.

The first 56 episodes of the show are being aired for free on Chinese video streaming platform iQiyi, which holds exclusive rights to the drama. For a fee, iQiyi members can watch eight more episodes.