The sticky note copied the look of a 10,000 yen banknote

Staff in a grocery shop in the north of Japan have apparently been taken in by a sticky Post-It-style note in the shape of a million yen bill, it’s reported.

The fact that the largest Japanese banknote is 10,000 yen (£62) was lost on the cashiers. Nor did they notice that Yukichi Fukuzawa – the influential Japanese writer whose face adorns the country’s currency – sports a “wry smile” on the single-sided fake bill, the Mainichi Daily News reports.

Local police say they are investigating a possible forgery case. But this is not the work of a master forger. The note’s provenance is rather more straightforward – it’s a novelty item produced by a company based near Osaka that stopped making the fake money stickers in October 2012 after several were passed off as real currency.

After the latest incident, the company has decided to stop selling its remaining stocks of the comedy banknotes. It is illegal under the Control of Imitation of Currency and Securities Act to manufacture products that “could be mistaken for genuine bills and coinage”, the paper says.

Genuine 10,000 yen banknotes, on which the spoof note was modelled