Casio has officially announced the G-Shock GMA-S2100PR-4AJR, a fresh pastel pink take on the popular compact octagonal shape widely known among watch enthusiasts as the CasiOak. Arriving in October for approximately $122 (¥18,700 including tax), the timepiece serves as the fourth release in Casio's series supporting Pink Ribbon breast cancer campaigns in Japan. Five percent of all domestic sales will be donated directly to J.Posh, a certified non-profit organization that has spearheaded screening access, awareness programs, and patient support in Japan for over twenty years.
Unlike conventional charity tie-ins that heavily lean on loud logos or overt branding, this edition keeps its message understated. Finished in soft pastel pink across its entire case, bezel, and strap, the watch places its defining thematic detail at nine o'clock, where the small day-of-the-week sub-dial hand carries a subtle pink ribbon motif.
An Understated Design with Purpose-Driven Details
The GMA-S2100PR-4AJR builds upon the downsized octagonal silhouette of the GMA-S2100 line, engineered specifically to fit slimmer wrists comfortably without abandoning G-Shock's hallmark toughness. This release continues an annual tradition for Casio Japan, following previous Pink Ribbon entries like the GMA-S2100P-4A, the DW-5600PK-1, and last year's GMA-S145PK-4AJR. The new model carries a modest price increase of roughly $4 (¥550) over last year's iteration while remaining priced under $125.
Rather than adopting glossy or reflective surfaces, the entire exterior utilizes a matte pastel finish that softens the sharp geometric angles of the octagonal bezel. The main dial retains tonal pink hour markers and hands treated with Neobrite luminous material for low-light legibility. To mark its special status, the watch ships in dedicated thematic packaging that matches the pink palette of the initiative.
Lightweight Carbon Core Guard and Bio-Based Materials
Beneath the muted pink exterior lies standard G-Shock structural protection. The inner case uses Casio's Carbon Core Guard architecture, leveraging carbon fiber-reinforced resin to protect the module against extreme impact and shock. Outer components emphasize environmental sustainability by utilizing biomass plastics derived from renewable organic feedstocks for the bezel and resin band.
Despite its rugged construction, the watch keeps a very trim profile on the wrist. Measuring 46.2 mm tall, 42.9 mm wide, and 11.2 mm thick, the entire piece weighs just 41 grams. The flexible resin band accommodates wrist sizes ranging from 140 mm to 205 mm. Standard hardware credentials include 20-bar (200-meter) water resistance and a scratch-resistant mineral crystal glass cover.
Daily Utility and Core Module Specifications
Functionally, the internal quartz module delivers standard digital-analog G-Shock features. It includes world time tracking across 48 cities (31 time zones plus UTC), a 1/100-second stopwatch for timings under an hour, a 24-hour countdown timer, five daily alarms, and a full automatic calendar programmed through the year 2099. Timekeeping precision is rated at plus or minus 15 seconds per month.
For viewing in complete darkness, the dial is equipped with dual white LED lights (Super Illuminator) that illuminate the analog dial and the digital LCD window independently, featuring selectable afterglow durations of 1.5 or 3 seconds. Additionally, a built-in hand retraction function moves the analog hands out of the way at the touch of a button whenever they obstruct the digital readout.
