Photo/Illutration The Tempo Rubato, a wrist-worn metronome created by watchmaking student Gaku Okada for his graduation project (Photo taken by Precision Watch Tokyo Co.)

For his graduation project, Gaku Okada decided to redesign the metronome, a wind-up device that is typically pyramidal in shape, around 23 centimeters tall and used to help musicians mark time. It is often found atop a piano.

The 22-year-old managed to pack all that into something that can be worn on the wrist.

His Tempo Rubato is the world’s first mechanical metronome based on the mechanism of a wristwatch. Tempo Rubato is a musical term in Italian.

Okada set his mind to work after consulting a world-renowned independent watchmaker and winning its support.

The Tempo Rubato consists of a case measuring 39.5 millimeters in diameter with a hand in the center that swings from side to side.

It starts when a button on the lower left of the case is pressed and stops when the button is pressed again.

The rhythm can be adjusted by rotating a ring-shaped part on a side. The tempo increases when it is turned to the right and decreases when it is turned to the left.

Normally, mechanical mechanisms are affected by vibration.

But the Tempo Rubato won’t slip out of sync even if the wearer is playing the drums. The wearer can even change tempo by turning the ring while playing.

The stainless case is so finely polished it is hard to believe it is the work of a student and not that of a manufacturer.

BUILDING OWN BRAND

Okada is a student at Hiko Mizuno College of Jewelry, a vocational school for jewelers and watchmakers in Tokyo.

The Hokkaido native started playing the drums when he was a grade-schooler and performed with a jazz band through high school.

Okada decided to pursue a career in watchmaking because he was nimble with his fingers, but didn’t want to sever his ties with music.

The watchmaking apprentice began working part-time at independent watchmaker Precision Watch Tokyo Co. in February last year.

The company has two renowned independent watchmakers in its ranks: Hajime Asaoka, who manufactured Japan’s first wristwatch equipped with a tourbillon, a complex mechanism to increase accuracy; and Jiro Katayama, who received a prize at an international wristwatch competition held in Switzerland in 2024.

“Asaoka-san gave me a lot of advice on design and layout,” he said. “I can learn a lot from both men even after I finish school.”

Okada intends to set up his own brand in the near future. In the meantime, he is working on an improved version of the Tempo Rubato that works both as a metronome and a wristwatch for release in January 2026.

He is now hard at work designing parts for the new model, which he expects will be almost the same size as the original.

“I want to win an international prize for wristwatches, so people will learn about my watches,” he said.

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