G-Shock’s Most Casual CasiOak Also Wears the Watch’s Most Formal Bezel Yet

The katana hand, cherry blossom dial and roman numeral bezel come courtesy of a Japanese rock band.

the dial, bezel, and pushers of a Casio G-Shock watch

Published March 17, 2025

·

Updated April 10, 2025

Every product is carefully selected by our editors. If you buy from a link, we may earn a commission. Learn more

There have been dozens of variations in the G-Shock GM-2100 series, affectionately known as the “CasiOak.” But one of the best-looking, and arguably the most unique of all, has just come from a Japanese rock band.

For those unacquainted with the Japanese rock scene, One OK Rock has a sound akin to 2000’s American pop-punk and is a pretty big deal in their native country.

a Casio G-Shock watch with a dark purple dial, silver bezel and white strap — Theis G-Shock GM-2100 is a collaboration with Japanese rock band One OK Rock.

To celebrate the 20th anniversary of the brand’s debut album, One OK Rock has teamed up with Casio for a special edition GM-2100. The band’s bassist, Ryota Kohama, helped design the cherry blossom dial, cartoon katana sub-dial hand and Roman numeral bezel.

a black and white photo of the Japanese rock band One OK Rock — One OK Rock wearing the band’s signature G-Shock GM-2100.

Even if you have never heard of the band, this is a gorgeous G-Shock “CasiOaks” and given its limited release and exclusivity to the Japanese market, it will likely become a sought-after reference in coming years.

Not your typical rockstar watch

This GM-2100 is surprisingly bright and beautiful for a watch designed by a rockstar. Japanese cherry blossom petals adorn the dark gray dial as a nod to the brand’s native land.

the swod hand sub-dial of a G-Shock watch — The day sub-dial has a cartoon katana sword hand.

Roman numerals are a strikingly odd sight on a G-Shock bezel, but it somehow works on the notoriously tough digital-analog watch. The one has been replaced with a circle to align with the band’s name.

The hand on the date sub-dial is commonly utilized for GM-2100 collaborations. In this case, it is a cartoon katana sword from the band’s anime iconography.

the case back of a Casio G-shock watch — The case back is engraved with One OK Rock’s logo.

A semi-transparent, cloudy white strap creates a light and airy feel. The pin-buckle is engraved with a Roman numeral thirteen, which matches one of Ryota’s tattoos.

Still a G-Shock

Under the fancy dressing, this is still a G-Shock. It has all the features and reliability that made the GM-2100 a fan-favorite.

the package for a Casio G-Shock watch — The One OK Rock G-Shock comes in a special display box.

It has a shock-resistant resin case with a polished steel bezel and brushed steel case back. The digital features include a 1/100th second stopwatch, an automatic calendar and a world time digital display.

An alarm feature can be set with up-to five different times. When the minute hand is covering the digital screen, it can be temporarily moved with the push of a button.

a Casio G-Shock watch with flower pedals on the dial — The One OK Rock G-Shock GM-2100 is one of the best-looking versions ever.

One OK Rock did an excellent job of embracing Japanese culture for the brand’s signature watch, making it appealing to G-Shock fans who have never heard their music. The cherry blossom dial and Roman numeral bezel alone make this one of the most unique and beautiful “CasiOaks” out there.