History of the G-Shock Mudmaster and Mudman Series of Mud-Resistant Watches

Compared to iconic and classic G-Shock series like the DW-5600 and DW-6900, the Mudmaster is a relative newcomer yet also one of G-Shock’s most recognizable and popular series. It is arguably the most successful of the Master of G series of professionals-use watches. The Frogman and Rangeman are also championed, but the Mudmaster has included multiple subseries that have sold well simultaneously, and the Mudmaster played a large part in G-Shock gaining mainstream worldwide acceptance with its more expensive models. Originally launched in 2015, the history of the Mudmaster’s origin begins all the way back in the 1980s and is intertwined with other series like the Mudman and Rangeman.

Origins: DW-5500 “G-Shock II” and Mudman Series

G-Shock II and Mudman Mud-Resistant Watches

The Mudmaster is essentially an analog-digital version of the Mudman line of mud-resistant watches. What does mud-resistant mean? Aren’t all G-Shock watches protected from mud if they are water-resistant to 200 meters? It’s not that mud is going to break a non-mud-resistant G-Shock (although it may require some bezel disassembly and extra cleaning), but it may get it in the way of operating it effectively in the field. What all mud-resistant G-Shock watches have in common is a protected button structure, meaning that they have some sort of covered button guards that are sealed to prevent intrusion by mud and other debris like dust and sand. During the era of the first mud-resistant and Mudman models, most other G-Shock watches had very small buttons. The button guards ensure that mud won’t get in the way of operating the buttons, and they also make the watch easier to use when wearing gloves.

The Mudman series traces its origin to the DW-5500 (above left) in 1985, which was also known as “G-Shock II.” This series was not officially named Mudman, as it was just an unofficial nickname then, but it was officially designated as mud-resistant by Casio. The 5500 line would experience a revival by Casio in the 2000s in the form of various subseries, but the DW-D5500BB-1 from 2018 was the last new model.

The first official Mudman series was the DW-8400 (above middle) in 1995 featuring a mole as its mascot. The analog-digital AW-570 appeared in 1997. (The anti-magnetic AW-570 was sold as both a Gaussman and a Mudman, depending on the region.) The DW-8400 ran until 2001 and was succeeded by the rally racing-inspired G-9000 (above right) and GW-9000 in 2006. The G-9000 is still active in the U.S. (as G9000) and other countries, and it is still a unique series with features such as two stopwatches, 5 independent multi-function (not just daily) alarms, flash alerts, and up to a 5-second EL backlight duration.

G-Shock Mudman GIF

In 2011, the G-9300 and GW-9300 series introduced the Twin Sensor (digital compass and thermometer) to the Mudman line. The G/GW-9300 remains active and is the smallest G-Shock watch with a compass sensor, although it is still considered a relatively large size.

 G-Shock G-9300 Mudman with Mud Resistance

G-Shock launched the GW-9500 with the Triple Sensor in 2023, which was a major upgrade to the Mudman line and the first G-Shock with a duplex LCD display.

G-Shock Mudman GW-9500


Other Precursors: Rangeman GW-9400 and Gulfmaster GWN-1000

Toughest G-Shock GW-9400-1 Rangeman Survival Watch

The Rangeman GW-9400 made its debut in 2013 and was an upgrade to the Riseman GW-9200 which was equipped with a pressure sensor (with altimeter and barometer) and thermometer. (The Riseman began in 1997 with the DW-9100.) The Rangeman added a compass, making it the first G-Shock watch with the Triple Sensor and positioning it as one of the top digital-display series by combining the features of previously groundbreaking series like the Riseman, Raysman (Tough Solar), Wademan (compass), and Antman (radio-controlled time adjustment). Another innovative feature that would later be adopted by the Mudmaster was the Rangeman’s new style of button guards that used a cylindrical shaft. Although the GW-9400 was not designated as mud-resistant in the official specifications from Japan, Casio Europe did designate it as mud-resistant and Casio America has referred to it as such in marketing materials. This style of button, which included a gasket in the shaft, was a big improvement over the previous Mudman buttons, as it was much easier to press. (The new Mudman GW-9500 is also equipped with this style of button guard.)

G-Shock Rangeman Cylindrical Button Guards

The GW-9400 would go on to be extremely popular over the years and is still active today, with the occasional new model released and as part of the Love The Sea And The Earth limited series from Japan.


The Gulfmaster GWN-1000 was the first analog-digital G-Shock with a Triple Sensor, and it introduced a larger Pro-Trek-like display to G-Shock for the first time. As an upgrade to the Gulfman, it also had a tide graph and moon data. Although it didn’t reach the heights of other Master of G series in terms of popularity, its larger analog-digital style paved the way for the Mudmaster.

GWN-1000B Gulfmaster

The First Mudmaster: GWG-1000

G-Shock Mudmaster GWG-1000

The Mudmaster GWG-1000 was introduced in 2015, and Casio was able to capture the same magic as it did with the Rangeman. The Mudmaster adopted some of the eye-catching design elements of the Rangeman, such as the enlarged bezel with front screws, front light button, and sturdy button guards. Combined with the large analog-digital display, the Mudmaster looked familiar and certainly like a G-Shock yet also completely new. Equipped with the Triple Sensor, Tough Solar power, and Multi-Band 6 automatic radio time correction, it was the ultimate set-it-and-forget-it tool watch for the outdoorsman and a peak form for G-Shock design. While the technology of the GWG-1000 wasn’t new in comparison to previous series and was basically the previous year’s Pro Trek PRW-6000 in a G-Shock housing, what made it special was its unique style and extreme ruggedness. It took everything that was attractive about digital G-Shock watches like the Rangeman and put it into a larger analog form that exuded strength and confidence. It captured a unique space that was previously unserved by other G-Shock watches. Combining the best characteristics of the Mudman, Rangeman, and Gulfmaster, the GWG-1000 was expensive and high quality, but it wasn’t trying to be fancy or luxurious. Despite the $750 price in 2015, it was immediately very popular in the U.S. and Europe.


Mudmaster GG-1000 and GSG/GWG-100: The “Junior” Mudmasters

G-Shock Mudmaster GG-1000 Watches with Twin Sensor

Following the success of the GWG-1000, the GG-1000 series was released in 2016. This was a smaller and more affordable watch without Tough Solar and Multi-Band 6 but with a Twin Sensor (compass and thermometer). The GG-1000 was also very successful and continues to be sold with an MSRP of $350.


In 2017, the GSG-100 (with Tough Solar) and GWG-100 (below, with Tough Solar and Multi-Band 6) offered another smaller and more affordable Mudmaster style but without any sensors. They were also one of the few G-Shock series offering the Neon Illuminator blacklight LED, but these series never caught on as much as the GG-1000. The GWG-100 is still available in Japan.

G-SHOCK GWG-100 MUDMASTER GWG-100-1A GWG-100-1A3 GWG-100-1A8

First Bluetooth Mudmaster: GG-B100

G-Shock GG-B100 Mudmaster with Quad Sensor Step Counter and Carbon Fiber Bezel

In 2019, the GG-B100 added Bluetooth smartphone link and a Quad Sensor (Triple Sensor plus step counter), but it did not have solar power or Multi-Band 6. Using Bluetooth combined with the smartphone app offered functions such as auto time correction, auto altitude calibration, watch settings adjustment, adjustable mode order, Mission Log (to track waypoints and altitude), and Location Indicator. The Location Indicator was limited to being able to save a location only of a current position where the user is at (to act as a backtracking tool), which would later be upgraded and expanded in the Mudmaster GWG-B1000. The GG-B100 was also the first Mudmaster with a Carbon Core Guard case made of carbon fiber-reinforced resin. Other unique features were the resin case back cover and carbon fiber bezel. The GG-B100 remains the only Mudmaster series with a step counter and is still active with an MSRP of $380.


GWG-2000: A Structural and Cosmetic Update

G-Shock Mudmaster GWG-2000 with Carbon Core Guard and Forged Carbon

Launched in 2021, the Mudmaster GWG-2000 was mainly a structural and cosmetic update to the GWG-1000, as all the functions were the same. It’s not that the GWG-1000 had any problems that needed to be addressed, but its very large size made it impractical for some people to wear. Following the trend toward smaller and lighter watches, the GWG-2000 adopted a Carbon Core Guard case with a width that was 1.7 millimeters smaller and a thickness that was 1.9 millimeters thinner. (The size difference is more pronounced when seeing them side by side or in person.) Although it’s still a large watch, the GWG-2000 is able to accommodate a wider range of wrist sizes. It also upgraded the mostly resin bezel of the GWG-1000 by adding a large stainless steel bezel ring and forged carbon bezel guards. This resulted in a more premium look, but it had the same $800 price of the GWG-1000 at the time.

G-Shock Mudmaster GWG-2000 Versus GWG-1000

Image via Gi-Shock-Go


GWG-B1000: A Return To Form

G-Shock Mudmaster GWG-B1000

The Mudmaster GWG-B1000 will be launched in October 2023 and all indications suggest that it will be another success. The GWG-B1000 has the Triple Sensor, Tough Solar, Multi-Band 6, and Bluetooth smartphone link, making it the first G-Shock or Casio watch with such a combination. It has the Mission Log and Location Indicator like the GG-B100, but this new version of the Location Indicator can edit the Location Memory to any point by using a map on the smartphone app. The GWG-B1000 also has an exterior update with a distinctive yet familiar style. It is a Carbon Core Guard model that is around the same size (but slightly smaller overall) than the GWG-2000, and it foregoes the forged carbon parts of that series in favor of DLC-coated stainless steel bezel guards combined with carbon fiber-reinforced resin side guards. The new style of analog-digital display is a first for Casio and features dedicated subdials for the altimeter and barometer readings and bearing indicator. It also adds sunrise and sunset time like the GW-9400, GG-B100, and GW-9500. While the current G-Shock lineup has been inundated with fashion-oriented colorways targeting new customers, the introduction of the Mudmaster GWG-B1000 is evidence that G-Shock has not forgotten about its core fanbase.

G-Shock Mudmaster GWG-B1000


Thanks to ShockBase and “Discover G-Shock” on the Casio Watches app for providing images and information.

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