Rolex is, without doubt, one of the biggest and most recognised brands on the planet. The stories behind the company are as fascinating as they are numerous, with Rolex’s involvement in exploration, scientific advancement and the arts. From setting new land-speed records to exploring the deepest marine trenches on earth, Rolex has always engaged with projects in a philanthropic way and also to test the limits of its timepieces. Like many classic designs over the past decades, the Rolex Oyster has gently evolved but primarily remains true to its roots. Within the Rolex line-up of sports watches there is a watch that has been a constant since 1953 – 65 years – that is showing no signs of going quiet any time soon: the Explorer.

The story begins in 1952. It was a time when some of the world’s leading explorers were on the cusp of reaching the highest point on the planet — the peak of Mount Everest. Many attempts had been made and many lives lost, but the British mountaineers of the early 1950s were ultimately the men that would conquer the mighty mountain. Rolex was adamant that it wanted its watches on the summit and so, in 1952, the company equipped the British climbers with large Oyster watches. These watches were what collectors now refer to as pre-Explorers, essentially prototypes of what would ultimately become the Explorer.

The Big Eggs

In 1952, a number of climbers traveled to the Tibet/China border as part of a research trip in preparation for the 1953 assault on Everest. The destination was a mountain called Cho Oyu, 20km to the west of Everest. Included in the party were some of the key players in the famous 1953 expedition including Edmund Hillary, Charles Evans and Alfred Gregory. The watches given to these climbers were ref. 6098 big bubbleback watches. Newly uncovered documentation informs us that Rolex provided 20 of these 6098s for the team in two batches (the first seven in 1952 to the advance research team and the second batch to the remaining expedition members who did not go on the research trip).

The big bubbleback watches are more commonly known by their Italian nickname — “Ovettone” — and are key watches in the development of the Explorer. The story began in the late 1940s with the 5020 series watches. Ovettone, Italian for “big egg,” describes the large domed casebacks and crystals. The second series of Ovettone watches that Rolex produced were ref. 6098s (the Everest watches) which, like the 5020 series, were of monoblocco construction (the mid-case and bezel being made from one block of steel) and featured the newly designed Super Oyster Crown, which didn’t screw down but pushed in like regular dress watches. The 6098s were powered by the A296 perpetual movement, which was very thick and necessitated the prominently domed caseback. The 6098s were also chronometer-rated and the accuracy of these watches was one of the key aspects that Rolex was keen to see test results of when the expedition team returned.

Never standing still, this was a time of fast turnaround in research and development at Rolex, and later in 1953 Rolex launched the improved pre‑Explorer ref. 6298. This watch now had the new three-piece case with separate mid-case and bezel. The bezel was used to secure the new tropic crystals to the mid-case and create a watertight system. The previous Super Oyster Crown had proven prone to leakage and so the 6298s had the new “brevet”/ cross (+) 6mm screw-down crown. Still using the A296 calibre, the watch retained the large domed caseback and is very much an Ovettone.  Both the 6098 and 6298 featured characteristically 1950s Rolex Oyster dials with closed minute track, applied arrow hour markers and applied Rolex coronet. Today, collectors refer to these as the “Everest” dials.

The official 3-6-9

While it had been used previously, Rolex officially rolled out the black “3-6-9” dial with refs. 6150 and 6350 – the successors of the 6098 and 6298. Again, both references used the A296 “big bubbleback” movement and the three-piece Ovettone cases. The difference was the dial layout. This was the true origin of what we see today on the Explorer. The inverted triangle at the top of the dial, printed Rolex text and coronet and the painted 3-6-9 numerals. The addition of Mercedes-pattern hands also came with refs. 6150 and 6350, although there were watches that were fitted with “pencil” hands, like those seen on the ref. 6204/5 Submariner too. The only difference between these two models was that the 6150 was designated “Precision” and the 6350 was chronometer rated and stamped with the words “Officially Certified Chronometer” (OCC). Yes, they used the same movement but the OCCs were fine-tuned to better precision. The 6350 was also the first reference to bear the mighty moniker — Explorer! To many collectors, this watch is the first proper Explorer. Collectors particularly look for the very rare version with a honeycomb dial; it is stunning.

In the mid-1950s, Rolex introduced calibre 1030 – its first complete in‑house built and designed movement and it was also chronometer rated. This next-generation movement required a new Explorer, and so the Wilsdorf empire gave birth to the ref. 6610 in approximately 1956. The newly launched calibre 1030 was a lot slimmer than its bubbleback predecessors and so a new case design was produced that was still well-proportioned at 36mm with a 20mm lug width. The slimmer movement meant that a flatter caseback could be fitted to the watch and it was this shape that became the standard for many years to come.

The New Looks

The 6610 also fully embraced the standard Explorer aesthetic. The dials had the inverted triangle at 12 o’clock, the 3-6-9 numerals and the now-standard Mercedes hands. All the dials were “gilt,” referring in Rolex terms to the glossy black dials with text in a gold (gilt) colour. The text is not printed on the gloss, but is actually relief print and the gilt text is the brass baseplate of the dial showing through; a production method known as galvanic process. The dial then had a lacquer applied to protect it. There are some very rare 6610s that had an additional line of text printed on the top of the dial in either red or silver; namely a depth rating (50m = 165ft). This was a way for Rolex to demonstrate the capabilities of the watch for all sports and methods of exploration. Another rare version of the 6610 had a painted white seconds hand; with Rolex, it is always about the tiny details.

In 1963 Rolex unveiled what would become one of the longest-running sports watch references, the Explorer ref. 1016. Production ceased in 1989 and in essence not a lot changed on the watch in that time, except some minor details – which is what it’s all about. Again, the 1016 was heralded by the use of the latest movement improvement by Rolex, the calibre 1560. A chronometer-rated movement, it became the staple in Rolex Oyster watches of the era. A decade later there was minor improvement to the calibre with the introduction of the 1570 which had a hacking (or stop-seconds) feature added. The 1016s were also rated to a slightly deeper depth rating at 100m.

One of the biggest changes that occurred in the lifespan of the 1016 Explorer was the shift in what was used for the luminous materials on the dials in the hands. Up until the early- to mid‑1960s, radium had been used. But it became apparent that it was completely unsafe and had potentially catastrophic effects on health, so Rolex moved to using the safer option of tritium. This was signified by the new “Swiss T<25” or “T Swiss T” on the bottom edge of dials replacing the “Swiss” that had been there previously. This switch began in 1963 and was transitional over a number of years. In the late 1960s, a new type of dial began to appear on Rolex sports watches and, relevantly here, the 1016 Explorer. Known as “matte dials,” there was a matte-black finish and the text was printed onto the dial surface.

Towards the end of the 1980s, Rolex introduced the next-generation Explorer. The reference 14270 was a very different watch but, as per the Rolex way, the core DNA was still present. The acrylic crystal was replaced with a scratch-resistant sapphire glass, which gave the watch a more modern feel on the wrist. The dial, while maintaining the iconic 3-6-9 layout replaced the painted numerals with white gold numbers that were filled with luminous material; initially tritium and then in the late-1990s Super-LumiNova. The watch was powered by the newly introduced Calibre 3000. The 14270 ran for almost a decade until it was superseded by ref. 114270 in 2000; a watch with a second-generation 3000 series movement, the 3130.

The Vintage Dilemma

Collectors of Rolex watches are divided about what actually constitutes a “vintage” piece. The majority would probably argue that the switch from acrylic crystals to sapphire is the cut-off. As time passes, however, the early sapphire-crystal watches are becoming more sought after as acrylic (or Plexi) Rolex watches gain spectacularly in value. Another key point to note is that quality control and production was much tighter at Rolex by the late 20th-century, and so the multitude of small variations seen between the 1950s and 1970s in sports watches was largely eradicated by the 1990s.

However, there are some interesting small differences in these models. One is the vintage-esque drilled lug holes seen on early 14270s, which were phased out relatively early in the watches’ run.  In 1990 (where the corresponding Rolex serial numbers began with the letter “E”), the 14270 was produced with a dial version where the 3-6-9 numerals were filled with black enamel instead of tritium. This wasn’t received well and so Rolex reverted to filling the numerals with luminous material almost immediately. This version has been given the nickname “Blackout” by collectors and is probably the rarest modern Rolex watch.

Few and Far Between

All the watches discussed so far have been of very similar proportions, in that they were all 36mm cases with a 20mm lug width. There were Explorers made largely for the Commonwealth market that were a little smaller at 34mm and that have become a collecting theme in themselves. The majority of these Rolexes were sold in the UK and Canada and the sheer number of dial variations is staggering, with new, previously-unseen examples being found each year. The most common reference for these watches was 5500, which is famously the Air King reference and led to the collectors’ term “Air King Explorer” for these watches.

The most desirable of the 5500 Explorers is the black gilt dial 3-6-9 version. Identical in some ways to the reference 1016 gilt dial watches, the big difference was that these watches were not chronometer rated and so had the dial designation of “Precision” or “Super Precision.” The dials were manufactured using the galvanic process and are beautiful in their execution. Finding an original one is difficult, however, as the gilt dials are notoriously faked and so an expert eye is needed when buying one.

The other Explorer-dialled 5500 watches can be classed as “Dress Explorers.” In fact, some of the dials I have seen are almost identical to Air King dials save for the word “Explorer.” Variations include incredibly detailed guilloché (waffle or textured) dials with applied numerals at 3-6‑9, so-called “Bullseye” dials with the seconds track on an inner section of the dial and also two-tone versions (gold winding crown and bezel) in ref. 5501. The ref. 5700, typically the Air King Date, was also seen with “Explorer Date” on the dial. I have only seen a few of these over the years and the ones I have seen haven’t always been in the best condition. I have to say, though, that these 34mm Explorers are some of my favourite Rolexes and I’m always keeping an eye out for them.

And finally, in 2010 Rolex supersized the Explorer with the ref. 214270 at Baselworld. Featuring the Calibre 3132, the watch was housed in a big 39mm case (nearly as big as a Submariner) and the word “Explorer” had been moved to the bottom half of the dial. The other noticeable change was the removal of luminous material (by now Rolex’s blue Chromalight) from the numerals, which were solid white gold — remind you of the “Blackout” 14270? The lack of luminous material in the 3-6-9 was not well received (and the hands were criticised as being too short) and so the dial and hands were reworked for the current version. Collectors take note — the Mk1 214270 is surely a future rarity.