2021 was a big year for Seiko. As one of the big hitters in the watch world that can count on a good deal more than a century in watchmaking, its recent anniversaries have been celebrated to emphasise that fact – none more so than its 140th in 2021, which saw a huge number of new releases that became instant classics in the eyes of its devoted (and often fanatical) following.

Leaving its illustrious sister brand Grand Seiko and ultra-affordable Seiko 5 options aside, the range that's seen the most action when it comes to its 140th anniversary releases is undoubtedly the Prospex collection. A portmanteau of the phrase "professional specification", it sits in the mid range when it comes to pricing (with many models available around the £1,000 mark), but has come to be known as a collection that offers excellent value, taking advantage of high-spec in-house movements and offering build quality that's pretty much unrivalled in its ballpark.

The collection is diverse, but talking about Prospex, especially in the context of the mid-1900s, usually means talking about dive watches. While many of the top Swiss houses helped push the diver to becoming one of the quintessential tool watch styles in the 20th century, Seiko more than did its part from further east, developing early references that set new standards in both function and form, especially during a particularly prolific period in the 1960s.

The Prospex collection offers excellent value, high-spec in-house movements and build quality that's pretty much unrivalled in its ballpark

The 1965 Diver's Watch (often known as the 62MAS), released in 1965, was Seiko's first dive watch and is arguably the most famous of those originals. And the 1965 Diver's Reinterpretation that aimed to lovingly restore it for a new era – particularly the grey-dial SPB143, but also other core and limited-edition versions of the same model in different colourways – was an overnight hit, becoming one of the most talked-about and best-loved releases of the year outside of Switzerland. I own the SPB213, with silver-white sunburst dial and dark navy bezel, and can vouch for the watch typifying everything that people love about Seiko: in-built history, in-house movement, frankly ridiculous bang for your buck, beautiful design, and cult appeal despite its wide availability.

The 1968 Diver's Reinterpretation

Despite the 1965 Diver's Reinterpretation's enduring appeal, last year also saw a few other releases both in the limited-edition space and the core range, and the 1968 Diver's Reinterpretation, or SPB240, shares similar DNA to its peer from the Prospex range, but weaves in a history all of its own, as well as some subtle but beautiful design flourishes that set it apart from the SPB143 and its variations.

Most importantly, the movement is different. And not just a variation of the same theme, but a different beast entirely: the original 1968 Seiko Diver's watch, on which the 1968 Reinterpretation is based, was the first of Seiko's divers to use its Hi Beat movement, which oscillates at a faster-than-average rate of 36,000 vibrations per hour (equivalent 10 beats a second), and the Reinterpretation packages this up in the modern calibre 6R35, which also offers an exceptional 70 hours of power reserve.

Unlike the 1965, the 1968 Reinterpretation's core model is two-tone, and also ups the case size by 1.5mm to 42mm. Built in Seiko's stainless steel with scratch-resistant Super-Hard Coating, the SPB240's unidirectional dive bezel is coated in rose gold, creating a beautiful point of difference with its near neighbour and helping the watch to be more bold and brazen on the wrist. That along with the slightly bigger size means a dive watch that's not exactly inconspicuous – more Pelagos than Black Bay Fifty Eight – and there's pleasing heft and weight to the overall package, alongside a reliably well-built bracelet.

Elsewhere on the aesthetics front, there are other differences: the index at 12 o'clock gently shapes into a point, and the hands are also made in rose gold, echoed slightly by a slightly warmer coating on the indices to help the overall look meld together. Unlike the 1965 Reinterpretation, the screw-down crown is offset at 4 o'clock, a design feature more commonly associated with the Seiko 5 range but used in a fair few of the Prospex collection models, too. For those who look a little deeper, arguably the most visually pleasing feature is the lugs – a thing of beauty, gently curved like the side of the Batmobile, for a subtle but sleek and modern take.

Alongside the fact that it has a nearly identical price to the 1965, there's more than enough about the 1968 Diver's Reinterpretation to keep Seiko's fans intrigued, and offer an excellent alternative to the the more talked-about SPB143 that still pays homage to an standard-setting time in an the history of a truly iconic watchmaker.

£1,130, available at Seiko Boutiques; seikoboutique.co.uk