The researchers said the work bought by Liu did not even match the fake work on the stone in terms of technical sophistication, and was in fact coarse.

The technique the forger used on the stone originated in the Tang and Song dynasties and was aimed at protecting the original works. It was used in late Qing Dynasty (1644-1911) mainly for forging, the three researchers said.

They said they suspected the work even before it reached the auction house.

Liu told Sina.com yesterday that he had contacted Sotheby’s over the issue. The auction house has said it will invite experts to investigate the authenticity of the piece. Liu said that before bidding at the auction, he had consulted calligraphy experts who had vouched that it was genuine.

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