When author Mizuki Tsujimura was in elementary school, her teacher said to her, “You are 8 years old, but actually you’re only 2.”

Tsujimura’s birthday is Feb. 29.

Back then, she did not quite know what a leap year meant.

But she remembers feeling sort of happy that she was “still only 2.”

She only gets to celebrate her birthday every four years.

However, she wrote in her contribution to Asahi Shogakusei Shimbun (an Asahi newspaper for elementary school children) that she was actually lucky to have that birthday because it was easy for all her friends to remember it.

“Even if I were to be reborn, I would still like to have this birthday,” she concluded.

Today, Feb. 29, is a leap day.

The human-set time span of one year is different from the flow of time created by the sun and the Earth.

The Earth is not a perfect sphere and the movements of heavenly bodies vacillate.

A leap day is for coordinating all these variables and “synchronizing” them somehow.

There used to be such a thing as a leap month.

In ancient Japan, the new moon, or the first day of the lunar month, was called “saku,” and one “sakubo-getsu” denoted the interval between one saku and the next.

In the traditional lunisolar calendar, one year consisted of 12 sakubo-getsu, which added up to 354 days.

And to that, a leap month was added from time to time.

Nature fluctuates but humans have always sought unwavering time.

Astronomer Galileo Galilei (1564-1642) discovered the law of the pendulum in the 16th century.

After pendulum clocks replaced sundials, there were quartz clocks, and now we have optical lattice clocks that are believed to be the most accurate timepiece ever made.

But what, exactly, is time?

When I think about deep space, I become scared by the utter diminutiveness of my existence.

A haiku by Hyakusui Inaba captures a sense of loneliness and heartbreak evoked by the impermanence of life.

It goes, “Loneliness makes me four-legged in a leap year.”

--The Asahi Shimbun, Feb. 29

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Vox Populi, Vox Dei is a popular daily column that takes up a wide range of topics, including culture, arts and social trends and developments. Written by veteran Asahi Shimbun writers, the column provides useful perspectives on and insights into contemporary Japan and its culture.