Saturday marks Pi Day, the day to commemorate the mathematical concept of pi — which refers to the ratio of a circle’s circumference to its diameter. Many math scientists and students around the world celebrate pi every March 14, as its first three digits are 3, 1 and 4.

The U. S. House of Representatives has even passed a resolution designating March 14 as National Pi Day.

Some say this year provides an even more auspicious occasion to ponder the enigmatic, endless sequence of numbers that make up pi. (Its decimal representation, which supercomputers have carried to 13 trillion digits, never ends and never falls into a repeating pattern.) Or it’s another excuse to gorge on apple pies.

This year is special because, when the date is written in the U.S. style, it is 3/14/15, meaning the fourth and fifth digits of pi also match the date. The next time this will happen is 2115.

“Everyone is very excited about Pi Day this year for exactly that reason,” said writer Alex Bellos, author of a regular math column for the Guardian newspaper. “It only happens once a century, which makes it a once-in-a-lifetime event. For this reason there is much more publicity about Pi Day.”

In Japan, however, the day’s significance has gone largely unnoticed by much of the public, and celebrations seem to be few and far between.

The Mathematics Certification Institute of Japan, which administers math exams to both students and adult learners, designated March 14 as “math day” in 1997. But it has no commemorative events on pi planned for Saturday, according to an institute official.

One of the few celebrations taking place in the Tokyo metropolitan area on Saturday is a talk in Kashiwa, Chiba Prefecture, by KSEL, a group of science graduate students mostly from the University of Tokyo.

Math blogger Asuki Yokoyama will share with a lay audience tales of the quirky personalities behind six of the math geniuses in history, including Greek mathematician and philosopher Pythagoras and 17th-century Japanese mathematician Seki Takakazu.

“Instead of going too much into detail about math itself, we would like to focus on the people, talking about how they were attracted to math in the first place,” said Taiga Hamura, one of the KSEL members. “That way, we hope the participants will be motivated to learn more about math on their own.”

After the event wraps up at 3 p.m., the participants will celebrate the day by taking a group photo at “15:09,” corresponding with the first six digits of pi: 3.14159.

Meanwhile, Akira Haraguchi, a 69-year-old resident of Chiba Prefecture who made headlines in 2006 by reciting 100,000 digits of pi at a public memorization event, said his celebration of Pi Day will be a modest one.

“I haven’t done anything special on the day in the past,” he said. “This year I’ll ask my wife to increase the amount of dinnertime drink I can enjoy on the day.”

In 2010, he managed to recite 101,031 digits in public, and an NHK program will stage another public pi recitation event later this year, he said.

“I have been reciting more than 15,000 digits per day” since 2006, said Haraguchi, adding that recitation practice is like chanting a Buddhist mantra to him. To memorize as many digits as he can, he has developed a unique way of assigning sounds to every pi digit and using them to craft hundreds of fictitious stories. Many of the stories based on pi are about animals and plants, but some are about himself, he said.

And what’s the purpose of learning about pi, or math even? Most of us after school feel little affinity with pi, or any other math concept for that matter.

“Maths is important because it teaches us to think logically and I think it opens our minds to fascinating worlds,” Bellos said.

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