Yes, of course Emma Haruka Iwao ate some pie on Pi Day. It was apple, and it was good.

But it’s her high-school teacher back in Japan who should have his mouth stuffed, or at least be eating his words — the ones he used to nearly kill Iwao’s passion, and prevent her from recently setting the Guinness world record for calculating the most digits of pi.

“You may like computers,” the teacher told Iwao, “but you are not good enough.”

Iwao, 34, recalled this for me the other day with a little bit of embarrassment. She just wanted to talk about pi on March 14 (3.14, get it?), and the record, and didn’t want to make a big deal about it.

But I did, for it’s a symptom of a much bigger problem. I’ve read study after study about the low number of women in tech, and the struggles they encounter once they enter the male-dominated field. All kinds of groups have been established to lend support and provide network opportunities.

And here is a Guinness record holder whose teacher nearly squelched her ambitions in a single conversation. In one sentence.


“That’s exactly what happened,” Iwao said.

Ah, but for every soul-crushing comment, there’s an equal and opposite word of encouragement, which is what happened when Iwao entered the University of Tsukuba in Japan as an education major. Another teacher noticed the time she was spending in the computer lab, and suggested she change her course of study.

Fast forward to last week, in Google’s Seattle office, where Iwao was transferred from the Tokyo office last December as a cloud development advocate. Not long after her arrival, she started calculating the most accurate value of pi, which is the ratio of the circumference of a circle to its diameter. It’s an irrational number. Never-ending.

In the past, pi has been calculated using supercomputers, but Iwao chose to use the Google cloud for her equation.

The biggest challenge, she said, was having enough storage to crunch the numbers. The other challenge was to keep the program up and running for four months.

“Reliability was a challenge,” Iwao said. “If the computers were unstable, the program would have been disrupted.”

After 121 days, using 25 virtual machines and 170 terabytes of data (about the same amount found in the print collections of the entire Library of Congress, Google pointed out), Iwao had calculated the most accurate value of pi to 31.4 trillion digits, or pi multiplied by 10 to the 13th power. The previous record, set in 2016, calculated pi to 22.4 trillion digits.


So why should we care?

“Pi is used for everything,” Iwao said. “Whenever you see a round object in the physical world or computers. Designing buildings, building bridges and highways. It is important.”

Pi has long been used as a benchmark to test the reliability and performance of computers, Iwao explained. We used it to test the very first computers, then supercomputers and now the cloud.

Breaking the world record while using the cloud means that the cloud can be used for the areas that supercomputers have been relied on in the past.

Google has made the digits available as a snapshot that people can copy to create their own machines. It would take weeks to copy the data over a network, but because everything is in the cloud, it will now take less than 20 minutes, Iwao said.

Just a few days before it was announced that Iwao had broken the world record, University of Texas mathematician Karen Uhlenbeck was named first woman to be awarded the Abel Prize, known as the “Nobel Prize of Math.”

Iwao hadn’t heard this, but it was welcome news. It means things are changing not just for her, but every woman in her field.


“Whenever I meet a lot of women in tech and computer science, I often hear that their work and their accomplishments are not recognized, and they are not equally treated,” Iwao said. “And so being visible and representation is really important.

“I think more women now feel encouraged and inspired because I could do this,” she said. “Every woman can do anything in tech and computer science.”

Even if they want to go after Iwao’s new world record?

“I’m up for challenges,” she said with a laugh. “And if someone breaks the record very soon, I think that’s a good thing because I pushed them harder.”

In other words, she fed their passion. With pi.

Correction: This article was corrected on the morning of March 22, 2019. In an earlier version, the 2016 record for calculating pi to the most digits was misstated.