Akira Haraguchi says he was never a genius in school. But at 59, the Chiba man recited pi -- the ratio of the circumference of a circle to its diameter -- from memory to 83,431 decimal places.

"My school grades used to be always 3 out of a range of 1 to 5 at most Japanese schools, said Haraguchi, who set the new world record in July, beating the previous record of 42,195 decimal places set by a Japanese college student in 1995.

Haraguchi, a former corporate employee who now does volunteer work, said his challenge began when he was 50. His fascination with pi recitation dates back to around age 40, he added.