It was after a competition at the Dragon School in Umeå, on international pi day on March 14 last year, that Klaus discovered his ability to memorize pi decimals.
A few weeks ago, the teacher Mikael Frängsmyr Svahn filmed Klaus counting all the ten thousand decimals he learned flawlessly, two other teachers checked the numbers in real time.
"Not so good at names"
He has also memorized a lot of other things, such as basically all license plates in Nordmaling.
He also remembers dates.
- I'm not very good at remembering names, but when I try to memorize something, it goes well.
I tried memorizing random Finnish words once and I could probably rattle off all those words today, he says.
Klaus only needs to hear a few decimal places among the 10,000 he has memorized to then be able to continue counting from there.
Watch as the teacher Mikael tests his unique ability in the clip above.