The Mudmaster has always worn its overkill badge proudly. Since 2015, it’s been the watch G-Shock builds for people who want a watch that can literally tackle anything. It’s sealed against mud, sand, and fine dust that would kill most watches – the kind of thing you’d expect strapped to a wrist in a rescue helicopter, not photographed against a sunset.
Which is exactly why Casio’s latest move is such a fun one. Meet the G-Shock Mudmaster GG-B100XMH-5A, the mud-proof brute that just went gold.
Chasing the Golden Hour
The new colorway anchors Casio’s three-watch Master in Horizon Gold collection, inspired by that golden line where the earth meets the sky. And rather than slapping on a coat of paint, Casio started with the Mudmaster’s stainless steel bezel and finished it in a light yellow gold ion plating.
The supporting cast follows suit. Metal accents like the bezel screws get a brown ion plating treatment, while the case and strap are molded from dark brown bio-based resin.
The result feels less like jewelry and more like well-worn expedition brass. Gold hands and indices pop against the black dial, with a red seconds hand sweeping through for contrast. For a watch this aggressive, it’s a shockingly handsome package.
Still a Mudmaster Where It Counts
Now, if you’re worried the glam treatment softened anything underneath, don’t be. The carbon fiber-reinforced Carbon Core Guard case is still here, as is the mud-resistant button structure, the glass fiber-reinforced caseback, and 200 meters of water resistance.
The Quad Sensor array returns too, packing an altimeter/barometer, compass, thermometer, and step counter into the case. Bluetooth pairs the watch to Casio’s app for automatic timekeeping and Mission Log, which records your altitude data alongside route info pulled from your phone’s GPS.
One quirk worth noting: unlike its solar-powered Mudman and Gravitymaster siblings in the collection, this one runs on a CR2025 coin cell rated for roughly two years.
Big Wrist Energy
Make no mistake, this is still an absolute unit. The case spans 55.4mm top to bottom, stands 19.4mm tall, and weighs 104 grams. That’s nearly two centimeters of watch sitting off your wrist. But that presence has always been part of the Mudmaster’s charm.
Spec Sheet
Model: GG-B100XMH-5A
Collection: Master in Horizon Gold
Case Size: 55.4 x 51.3 x 19.4mm
Case Material: Bio-based carbon fiber-reinforced resin (Carbon Core Guard)
Bezel: Stainless steel with light yellow gold ion plating
Band: Dark brown bio-based resin
Water Resistance: 200m
Sensors: Quad Sensor (altimeter/barometer, compass, thermometer, step counter)
Connectivity: Bluetooth (Casio Watches app)
Battery: CR2025, approx. 2-year life
Weight: 104g
Pricing & Availability
The Mudmaster GG-B100XMH-5A is currently up for pre-order in Japan at ¥60,500 (~$383) ahead of its retail release later this month. There’s no word yet on a stateside rollout, so US buyers may be playing the import game for now.
Recap
G-Shock Mudmaster GG-B100XMH-5A “Master in Horizon Gold”
G-Shock wraps its ultra-rugged Mudmaster in a gold ion-plated bezel and earthy brown resin, keeping the Quad Sensor toolkit and 200m water resistance fully intact underneath the shine.
