TOKYO - He thinks it could have made him rich, but eventually the mahjong calculator that the new Japanese prime minister Naoto Kan invented when he was a student,  never made it to the production line.

Kan-san last week won the leadership of the ruling centre-left Democratic Party of Japan (DPJ). Nicknamed ‘Ira-Kan’ or ‘Irritable Kan’ for his fiery outbursts, the outgoing finance minister also has a populist flair and has long been a top player in the party he co-founded with outgoing premier Yukio Hatoyama.
As well as now being in charge of the world’s second-biggest economy, he is also a mahjong enthusiast and a part-time inventor.

Complicated

Back in the nineteen-seventies, when he was a student at the Tokyo Institute of Technology, Mr. Kan thought the point system used for calculating the gambling proceeds of mahjong quite complicated. So he developed a mahjong point calculator. He applied for a patent for the calculator in 1973, three years after graduating college, and it came through in 1977.
‘If all had gone well, I would have become quite rich, even if not quite as rich as Bill Gates’, he said in an interview, recounting how he unsuccessfully pitched his prototype to Nintendo and other electronics makers. ‘I became a politician because nobody put up money for my invention.’

Eventually, the machine found itself in the Mahjong Museum in Chiba, one hour drive from Tokyo. According to Takunori Kajimoto of the Mahjong Museum, the machine shows the correct number of points “when the winning player pushes buttons according to the correct number of minipoints, hans, and if he is East or another player”.
It is no wonder that Kan-san did not succeed in selling his invention. When provided with the data as mentioned above, even an average mahjong player produces the appropriate score in a split second - without any calculator or score-sheet, just by heart.

Photograph

The Mahjong Museum does not keep the calculator anymore in its collection, Kajimoto-san acknowledges: it was given back to the inventor. Only a photograph of the device is on display.
According to the Wall Street Journal, who spoke with the office of the incoming prime minister, Mr. Kans taste in games may have changed, in favor of another classic Chinese game: go.
“I haven’t heard of Mr. Kan playing mahjong recently,” a spokeswoman said.