In 2018, the 35th anniversary of G-SHOCK, Casio introduced the GMW-B5000D, based on the design of G-SHOCK's ORIGIN, the DW-5000C, but with a full metal exterior made of stainless steel. This model not only won the support of G-SHOCK freaks, but also created new fans. Later, titanium was added to the exterior material, and the GMW-B5000 series steadily expanded its lineup with IP color development and a variety of finishes to accentuate its looks. The MRG-B5000 is the most evolved form of such full metal ORIGIN, and it is not only a lineup of the MR-G, but it is also the “highest peak of full metal ORIGIN” that was produced under the theme of “mastering ORIGIN.” It is a model that can be positioned as the “pinnacle of full metal ORIGIN.”
It is characterized by its materials and structure. The case is made of 64 titanium alloy, the top bezel is made of COBARION, and the band is made of DAT55G (kind of titanium alloy), all of which are very hard materials. This is because the bezel of the conventional full metal ORIGIN is integrally molded, and if this structure is used as is, the concave surface of each material cannot be polished properly. Therefore, Casio disassembled the bezel into 25 parts. Even with the complex shape of the ORIGIN, Casio was able to polish even the smallest details to achieve an aesthetic worthy of the pinnacle of the G-SHOCK.
At the same time, however, the shock-resistant structure at the heart of the G-SHOCK was not without its problems. The GMW-B5000 series, which used an integrally molded bezel, had a cushioning material sandwiched between the center case and bezel, but the MRG-B5000's bezel was split into separate parts, making it impossible to incorporate the same shock-resistant structure as before. This is why the Multi-Guard Structure was invented. The T-shaped parts with plate springs sandwiched between them are placed at the four corners of the case, and they slide up and down to create a bumper-like effect, while cushioning material is also applied to the top, bottom, and sides of the case to create a new structure that can withstand impacts from all directions.
One of the triggers that led to the creation of this challenging ORIGIN was the existence of COBARION, an alloy from Japan.
Professor Akihiko Chiba of Tohoku University developed COBARION in the mid-1990s, when he began researching the domestic production of cobalt-chromium-molybdenum alloys as a medical metal. The main objective was to eliminate nickel from the alloy, which was already a problem in Europe at the time and caused allergic reactions. At the same time, the alloy needed to be easy to process and durable enough to be used for medical prostheses, which was the main application of the alloy. In order to solve these problems, Mr. Chiba continued to study the structure of the material, and discovered the importance of nitrogen in the process. The addition of nitrogen, which was previously thought to be an impurity in the alloy, resulted in high hardness and excellent scratch resistance, and also made the alloy easier to process at high temperatures. Moreover, when the surface was polished, it was found to have a brilliance comparable to that of precious metals.
EIWA, which has its office in the steel town of Kamaishi City, Iwate Prefecture, was in charge of the development of the new alloy COBARION, which was born in this way. Since it was a new alloy, there was a lot of trial and error before it could be manufactured stably, and in order to further promote this material, it was necessary to explore applications other than medical use while continuing to promote it. It was during this time that they met G-SHOCK.
COBARION has a high hardness and a beautiful luster when polished. The fact that it originated in Japan, and the passion that was poured into this material by a researcher and a company that sympathized with his enthusiasm, has much in common with the spirit of challenge that G-SHOCK has always practiced. This was the driving force behind the creation of the MRG-B5000, which combines a highly difficult material with a new shock-resistant structure.
All content including images is credited to Hodinkee.