Casio

Most watch brands sell a movement in a case. Casio sells a sealed electronic module in a structure designed to keep shocks away from it. Everything distinctive about the company follows from that difference, including the fact that its cheapest watch is more accurate than almost any mechanical watch at any price.

Who owns Casio and where the watches are made

Casio Computer Co., Ltd. is an independent Japanese company listed in Tokyo, founded by the Kashio brothers in 1946 and known first for calculators. Watches arrived in 1974 and remain one division among electronic keyboards, projectors, calculators and label printers. That matters more than it sounds: Casio approaches a watch as a consumer electronics product with a bill of materials and a production run, not as an heirloom.

Volume production runs from plants in Thailand and China. Yamagata Casio, in northern Japan, runs the premium line that assembles the metal MR-G and MT-G models, and those are the watches Casio labels as made in Japan. Everything else is designed in Japan and built elsewhere, which is precisely why an F-91W costs what it costs.

How a G-Shock is actually built

The first G-Shock, the DW-5000C of 1983, came out of a development project with a target Casio has repeated ever since: survive a 10 meter drop, resist 10 bar of pressure, run for 10 years on a battery.

The solution was not to make the module stronger. It was to stop the shock reaching it. A G-Shock case is hollow, and the module sits inside on cushioning points rather than screwed hard to the case, so an impact travels through the outer resin, the bezel and the case back instead of through the circuit board and the stepper motor. The buttons are recessed behind guards, the glass sits below the rim of the bezel so it does not strike a surface first, and the strap is integrated into the case so the lugs, the traditional failure point of a watch, effectively do not exist. Our guide to shock resistance and durability explains why lugs and stems break first on conventional watches.

What the testing claims mean

Two different standards get mixed up here, and separating them tells you what the marking on the dial is worth.

ISO 1413 is the international standard behind the words shock-resistant on a watch. It specifies drops from about a meter onto a hard surface and an impact meant to represent that, after which the watch must still run within a permitted change of rate. It is a floor, and it is a low one. Casio's own protocol is far more demanding, involving repeated drops from around 10 meters, tumbling drums, vibration and temperature cycling, and specific models are additionally tested against methods drawn from MIL-STD-810, the US defense environmental test standard.

The F-91W as an industrial object

The F-91W was launched in 1989 and has barely changed since. It runs module 593, weighs around 20 grams, measures roughly 37.5 by 34.5 by 8.5 mm, and offers an alarm, an hourly signal, a stopwatch and an auto calendar. A CR2016 lithium cell runs it for about seven years. It sells for the price of two coffees.

Its most misunderstood specification is water resistance. The F-91W carries a plain water resistant marking at 30 meters, which means splashes and rain, not swimming and not showering. That is a general rule about markings rather than a Casio quirk, and our water resistance guide and the water resistance checker set out what each label permits.

What makes it interesting as an object is that it is a finished design. Nothing has been added because nothing needed adding, the tooling has been amortized for decades, and Casio still publishes the manual and still sells the parts. Very few consumer products from 1989 are still in production unmodified.

Modules, and why the repair economics are different

Look at the back of any Casio and you will find a module number: 593 on an F-91W, 1545 on a DW-5600. That number, not the model name, is the unit of repair, and Casio publishes a free manual for each one.

A mechanical watch is repaired by disassembling the movement, cleaning it, replacing worn parts and reassembling it, which is why servicing costs what it does. A Casio is repaired by swapping the entire module, or more often by replacing a battery and a gasket. The consequence is a hard economic floor: on a watch worth $20, a module swap plus labor costs more than the watch, so the watch is replaced instead. On a G-Shock worth $150 it is worth doing once.

The second consequence is less obvious and matters more for anyone buying a Casio to keep. Modules go out of production. Casio supports them for a period after the model ends and then stops, and a discontinued module with a dead circuit cannot be brought back. A mechanical watch from 1970 can be made to run again by a competent watchmaker. A digital Casio from 1990 with a failed module is a case, a strap and a memory.

Solar and radio, and what they fix

Two technologies remove the two remaining chores. Tough Solar puts a photovoltaic cell behind the display and charges a rechargeable cell, which removes the battery change and keeps the case sealed. Multi-Band 6 adds a longwave receiver that corrects the time against an atomic clock, usually overnight while the watch is still.

The six transmitters are worth knowing, because they are the limit of the feature. Two are in Japan, at Fukushima and in Kyushu. WWVB broadcasts from Fort Collins in the United States, DCF77 from Mainflingen in Germany, MSF from Anthorn in the United Kingdom and BPC from Shangqiu in China. That covers Japan, most of Europe, much of North America and part of China. It does not usefully cover Australia, New Zealand, South America, Africa, India or Southeast Asia, and no amount of putting the watch on a windowsill will change that. For those regions Casio's Bluetooth models, which set themselves from a phone, are the equivalent feature.

Where Casio sits against a mechanical watch

On timekeeping there is no contest. A cheap Casio module is specified in tens of seconds a month; an affordable automatic is specified in tens of seconds a day, and the good ones still drift more in a week than a Casio does in a year. Our answer on quartz accuracy gives the numbers, and the wider case is in quartz against mechanical.

The contest is about what you are buying. A mechanical watch is a repairable object with a long service life and a supply of parts that outlives its maker's interest in it. A Casio is a sealed appliance with a defined lifespan, and the trade you are making is permanence for competence. Against a smartwatch the calculation flips again, because a G-Shock needs no charging and no software updates, which our comparison of smartwatches and traditional watches works through.

Where Casio is weak

The failures are consistent and predictable, which is itself useful.

• Resin ages. Straps and bezels harden, crack at the stress points and yellow, particularly on white and translucent models. Ten years is a normal life for a strap. They are cheap and replaceable, which is the mitigation.
• Mineral glass scratches. Almost the entire range uses mineral crystals, and only the expensive metal models get sapphire. A well-used G-Shock face is a scratched G-Shock face.
• Displays and backlights fade. Electroluminescent panels dim with use and LCD segments can go, and neither is worth repairing on an inexpensive model.
• Size. G-Shocks are tall as well as wide. The shock structure needs the space, so a slim G-Shock is not really available, and small wrists are better served by the 5600 case than by the larger families.

What it costs, and who it suits

Indicative US prices, quoted before sales tax, which varies by state, and which move with market and discounting: an F-91W lands around $20, a standard DW-5600E around $70, a solar and radio-controlled square such as the GW-M5610 between about $150 and $190, and the metal MT-G and MR-G models from several hundred dollars into four figures. Casio is heavily discounted at general retailers, so street prices often sit below list, and buyers outside the US should expect local duty, distribution and tax to move all of these figures. A battery change with a new gasket and a pressure test typically costs $40 to $80. Resale is close to zero on standard models, with the exception of limited collaborations, which is a speculative market and not a reason to buy a watch.

Casio suits anyone who needs a watch to be a tool: shift workers, people who work with their hands, travelers, parents, divers who want a backup, and anyone who has already broken a nicer watch. It suits a first watch for a child better than anything else. It does not suit somebody who wants an object that will still be repairable in thirty years, and it does not suit somebody who wants the mechanical part of watchmaking, in which case Seiko is the place to start. If the appeal is a sealed, accurate, service-free watch but you want it to look like a conventional one, Citizen is answering the same question in dressier clothes.