On 25 December this year, it won’t just be a certain someone’s 2,019th being celebrated. For watch nerds and retro-tech geeks alike, it’s arguably a birthday of far more significance: the golden anniversary of the quartz-regulated, battery-powered, integrated-circuit wristwatch.

Christmas in Japan is a relatively new tradition, so back in 1969, Seiko thought nothing of launching its Astron on a day when most of the Western world was gorging obliviously on turkey, still wearing their lever-regulated, spring-powered mechanical tickers. Seiko also gave little weight to charging as much for the watch as Toyota did for a Corolla hatchback.

Fifty years ago, quartz timekeeping was, for the leading horologists of Switzerland, the US and Japan, nothing short of the Holy Grail and Moon Shot combined. As soon as the miniaturised integrated circuit became available in the 1960s, watchmaking’s space race was off the blocks with not two, but five competing designs, from brands as diverse as Jaeger-LeCoultre, IWC Schaffhausen, Girard-Perregaux, Omega and Hamilton. But it was the Seiko 35SQ movement’s potent cocktail of tuning-fork quartz resonator, oscillating at 32,768Hz, with CMOS circuit and stepped-down 1Hz pulses that stuck.

It was a cocktail that proved a little too potent for traditional Swiss watchmaking. Once prices for quartz plummeted, the writing was on the wall. The so-called Quartz Crisis devastated the industry right through to the 1980s, when a miraculous turnaround was effected by two rather different phenomena. First, there was the cheap and cheerful, but crucially Swiss-made Swatch watch of 1983, whose success bolstered all the consolidated, ailing brands of yore. Second, a newfound love for the mechanical watch, this time as a lasting luxury object. Remedial soulfulness for a disposable, increasingly digital world.

For this reason, the purists will always go mechanical. But quartz now has history. In 50 years, it has grown its own soul. The technological principles even feel rather rudimentary today, especially compared to an Apple Watch, but they have never been bettered (and neither have the 200-year-old principles that underpin every mechanical watch, come to think of it).

Bottom line: there’s no shame in quartz. Quartz is cool again, but if you’re going to invest in some top-end crystal action, you’d better know your stuff, just as any self-respecting watch fanatic would when it comes to his gears, springs and levers.

Before we start talking differences, however, it might surprise you to discover how similar things are.

At a very basic level, quartz and mechanical watches work the same way. A power source provides a constant impulse, which a regulator then ekes out as regular, iso-chronic pulses – pulses that move a geartrain, tick for the tock for the tick. The hours, minutes and seconds hands are each attached to three cogs in this geartrain, meshed together in a precise ratio of teeth.

Find out more at MR PORTER’s Luxury Watch Guide

Forgetting about the devastation it wrought on the Swiss industry and the purist snubs for a moment, let’s just pause to remind ourselves what an extraordinary thing the quartz watch is. For a start, it was the only major horological breakthrough of the 20th century. And it still makes up three-quarters of Switzerland’s now rehabilitated industry exports, while accounting for less than a fifth of those exports’ value – an extraordinary economy of scale that gets you a Swiss-made watch for an average of £175, which keeps time to an accuracy of 10 seconds a year, as opposed to a watch for £1,600 that loses or gains four or five seconds a day.

Today’s quartz watches are powered by a lithium battery, which feeds into an integrated electronic circuit, printed onto a silicon wafer, and in turn the movement’s regulatory heart, a tiny U-shaped quartz crystal, etched by photolithography from the raw material. Seiko grows its own quartz lozenges in-house, from seed crystal, inside towering, Alien-like autoclaves.

The circuit consists of 15 binary division stages that reduce the quartz’s resonating frequency of 32,768Hz to 1Hz. This one-second pulse activates a stepping motor, which gives out that classic tick, tick, tick as it powers the geartrain and hands.

We hardly need sell you on the unbridled joys of a mechanical watch. Or justify the hefty price tag for that matter. It is a vital piece of European history, which literally lives on your wrist. You yourself are breathing life into its ticking heartbeat with every gesture of your arm (if it’s an automatic with a spinning, self-winding rotor) or every morning when you pick it up from the nightstand and lovingly wind it up (if it’s a manual).

Furthermore, its open-source technology – never obsolete, always repairable – means that it will tick for ever, on the wrists of your offspring and theirs. A mechanical watch gives you the best cost per wear of your entire wardrobe.

Instead of a lithium battery, the powerhouse is a spring, made of cobalt-nickel-chromium alloy, coiled tightly inside a barrel. As it unwinds, the toothed circumference of its housing drives the geartrain, precisely ratioed, like in quartz watches, to drive the hours, minutes and seconds hands.

Left to unwind naturally, the hands would whizz around in a blur for 10 seconds before things came to an abrupt halt. What stops this happening is the escapement at the other end of the geartrain, which ekes out the flow of power over 40 or so hours (when you’ll need to rewind the mainspring).

The equivalent of the resonating quartz and integrated circuit, the escapement consists of a rocking, anchor-shaped lever, which alternately locks and unlocks the gears, allowing the mainspring’s power to escape gradually.

What regulates how regularly this locking and unlocking action happens (generally four times a second, as opposed to quartz’s 32,768) is the wristwatch’s equivalent of a swinging pendulum, a brass balance wheel that hangs from a flexible balance spring. The wheel oscillates back and forth by 270°, flicking the tip of the anchor lever left, then right, then left, then right.

A mechanical watch movement is like a finely tuned performance-car engine running at full tilt, 24/7. Like a car, it needs oils to run smoothly, oils that eventually harden and start acting like an abrasive. So, while it’s easy to pop a new battery into your quartz watch every few years, it’s just as crucial to get your mechanical watch serviced once in a while, even if things seem to be ticking over just fine.