When a bank customer spotted an elderly man scrutinising a RMB100 note as he waited in line eight years ago he decided to investigate further.

Upon discovering the old man was clutching a note containing a serious misprint – the watermark of Chairman Mao printed upside down – he asked the elderly customer if he would be willing to sell the note at face value. “My brother-in-law thought it was fun, so we exchanged the note for 100 yuan,” he told Sina News.

Little did either party know, the misprinted note was worth a fortune.

The RMB100 note with a reversed watermark of Chairman Mao. Photo: Sina News.

In June this year Mr He, a businessman from Wuhu, posted a picture of his curious note on online and was soon shocked to receive countless calls from people willing to pay huge sums for the bill, with offers starting at RMB700,000.

“An auctioneer from Shanghai said it was worth 2.3 million yuan,” he told Sina News.

He’s local bank certified the legitimacy of the bill, printed in 1999, after running it through a counterfeit detector, according to Anhui News.

Misprinted currency is generally withdrawn from circulation by the national bank, although it occasionally ends up in private collections.

People’s Bank of China in Tianjin. Photo: Wikimedia Commons.

A representative from the People’s Bank of China said that seven checkpoints are present in banknote printing plants to weed out any mistakes, according to Sina News.

He said the probability of misprinting money would be a million to one, and errors in printing the watermark are extremely rare.

Paul Benedict Lee

Paul Benedict Lee is an undergraduate law student at the Chinese University of Hong Kong. Paul has previously contributed to HK Magazine and Radio Television Hong Kong, covering issues ranging from local heritage conservation to arts features. He has also worked as a legal intern at local human rights firm Daly & Associates.