F-87W & F-91W

This is the watch that started everything for me. Not the F-91W that everyone knows. The one before it. The Casio F-87W, with its red border around the dial, the word "Lithium" printed right on the face, and an amber backlight that glowed warm when you hit the button. That was my watch. Somewhere around 1984 or 1985, this thing ended up on my wrist, and nothing has been the same since.

Historical context

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The F-87W came out in the mid-1980s, right in the heart of the digital watch era. It ran on Module 415 in the early production and Module 595 in later runs. The specs were almost identical to what the F-91W would later offer: a CR2016 lithium battery rated for about seven years, a stopwatch, a daily alarm, an hourly signal, and a backlight. But the details were different. The case had traditional lugs instead of the integrated strap design the F-91W would introduce. The dial had "Lithium" printed on it because in the mid-1980s, lithium battery technology was still new enough to be a selling point. Most digital watches at the time needed battery changes every year or two. Seven years was remarkable, and Casio wanted you to know it. By 1989, when the F-91W came out, lithium batteries had become standard and the text was removed.

And then there was the red. The F-87W had a red accent border around the dial, which made it visually distinct from its sibling, the F-84W, which had a blue border. Mine had the red. That red with the black case and the yellow text gave it a warmth that the later F-91W, with its blue accent ring, never quite matched.

But the real difference was the light. The F-87W had an amber LED microlight. Not the greenish-blue LED that current F-91Ws have. A warm, soft amber glow. And that amber light is specifically why I loved hitting that button so much. It was soft on the eyes, almost cozy. I would hide under blankets, crawl into dark closets, go under tables, anywhere dark, just so I could press that button and watch the display glow. I felt like a secret agent. I was watching Knight Rider on TV, watching David Hasselhoff talk into his watch to communicate with KITT, and then I would look down at my F-87W and press the light button and feel like I was doing the same thing. I was watching shows with countdown timers and bomb defusal scenes, and I would set my stopwatch and imitate what I saw on screen. The watch was not just a timepiece. It was an extension of every toy I played with and every TV show I watched. It was part of my imagination.

When the strap broke or got uncomfortable, I would take the head off and put it in my backpack. Just the module in a little pocket, like a pocket watch. I would pull it out to check the time and put it back. I did this for months before getting a new strap. A kid carrying a digital watch head in his bag like some kind of miniature instrument. Looking back, that might have been my first experience with the idea that the watch itself is what matters, not how you wear it.

The 1980s were a different world for watches. Digital dominated everything. The Swiss industry was in freefall from the Quartz Crisis. Their market share had crashed from over 50% in the 1960s to 24% by 1978. The number of Swiss watch companies dropped from 1,600 to under 600. Meanwhile, Casio, Seiko, and Citizen were putting calculator watches, game watches, and data bank watches on the wrists of every kid in America. Mechanical watches were what your grandfather wore. Digital was the future, and the future was accessible. For the price of a couple of comic books you could get a watch with a stopwatch, an alarm, a backlight, and a date function. The F-87W was exactly that kind of watch. Pure function, pure fun, at a price that put it on the wrist of anyone who wanted one.

The F-87W is discontinued now. It has been for decades. If you find one on eBay or a collector marketplace, expect to pay anywhere from $18 for a rough example to $200 or more for a mint condition piece with original packaging. There was even a TV Asahi branded Japanese domestic version, which tells you the watch had enough market presence in Japan for corporate tie-ins. It is genuinely rare at this point. The F-91W sells three million units a year. The F-87W is a collector's piece that most people have never heard of.

And that is where the story transitions. In June 1989, a designer named Ryusuke Moriai created his first watch for Casio. It was called the F-91W, and it was a direct successor to the F-87W. Moriai later became the chief designer of the G-Shock line, which tells you something about the caliber of mind behind this unassuming little watch. The design brief was simple: take what the F-87W did well and refine it. Build a watch anyone could afford, make it accurate enough to trust, and keep it running for years without maintenance. Moriai achieved all three goals so completely that Casio has never changed the design. The F-91W you buy today in 2026 is essentially the same watch that rolled off the line in 1989. 37 years of continuous production with no redesign. That is not a lack of innovation. That is a design so right the first time that there was never a reason to touch it.

What Moriai changed from the F-87W was subtle but important. He gave the case an integrated strap design instead of traditional lugs, which made it sleeker and more modern. He swapped the red border for a blue accent ring. He cleaned up the dial, removing the "Lithium" text. He kept the same essential functions, the same battery life, the same price point. The F-91W weighs 21 grams, runs on a CR2016 battery for about seven years, is accurate to plus or minus 30 seconds per month, and has a stopwatch, daily alarm, auto calendar, and LED backlight. The LED changed from amber to green over the years. Every decision in this watch was made to deliver maximum function at minimum price, and the result is something that Casio sells for roughly $15.

The engineering achievement is easy to overlook because the watch looks so simple. But that simplicity is the engineering. The Module 593 has a minimal number of components. Fewer parts means fewer failure points. The resin case absorbs shocks rather than transmitting them to the circuit. The LED backlight draws almost nothing, which is why the battery lasts seven years. The tooling for production was amortized decades ago. Casio produces approximately three million F-91Ws per year and has done so for 37 years. Over 100 million units sold. It is the best-selling traditional watch in human history. The IEEE inducted it into the Consumer Electronics Hall of Fame alongside the transistor radio and the Sony Walkman.

The cultural significance of this watch goes beyond sales numbers. Barack Obama has been photographed wearing one. So has Osama bin Laden. Neo wears one in The Matrix. Walter White wears one in Breaking Bad. At Guantanamo Bay, the F-91W was listed as a suspicious item because al-Qaeda reportedly distributed them at training camps. The alarm function, long battery life, and cheap availability made it useful as a timing component. Watch collectors with six-figure collections genuinely respect the F-91W. Not ironically. It represents what horology is supposed to be about at its most basic level: a device that tells time reliably.

If there is a criticism of either watch, it is the water resistance. Both the F-87W and F-91W are rated for splashes and rain, not swimming. The acrylic crystal will scratch over time. These are not complaints. They are the honest tradeoffs of watches that cost less than lunch.

I think about the F-87W differently now than I did as a kid. Back then it was a toy, a gadget, an extension of my imagination. Now I see both of these watches as genuine pieces of design history. The F-87W established the template in the mid-1980s with its red border and amber glow. Ryusuke Moriai took that template in 1989 and created something that has sold over 100 million units, been inducted into the same hall of fame as the transistor radio, and still costs $15. The one I grew up with, the F-87W with the red accent and the warm amber light, is now a collector's piece. Its successor is still selling three million units a year, unchanged. That kind of lineage, from my wrist as a kid to the most sold watch in history, is something I find genuinely remarkable. And it all started with a light button and a dark closet and a kid who felt like a secret agent.