Seiko Prospex 1965 Heritage Diver's SPB453J1

Imagen: Seiko, web oficial

The storyWhy this reference matters

In 1965 Seiko put its first dive watch on the market, reference 6217-8000, and collectors christened it the 62MAS. The nickname is not arbitrary: it contracts SeikoMAtic Selfdater, automatic with a date, and puts the 62 of the calibre in front. That watch is considered the first Japanese professional diver and opened a line that runs unbroken to today. Everything Seiko has done underwater since begins in that case.

The modern 62MAS reissues, the SPB143 series and its relatives, spent years as the way into a grown-up Prospex: 40.5 mm, 200 metres, calibre 6R35. In June 2024 Seiko rebuilt the whole family and tightened it point by point. Down to 40 mm, lug to lug cut from 47.6 to 46.4 mm, two tenths off the thickness, the screw-down crown sunk slightly so it stops digging into the back of your hand, and water resistance up to 300 metres.

The most argued-over change is on the dial. To meet the ISO standard for dive watches, the date moves to a small round window between four and five, with the date disc painted to match, and a full-size marker returns at three. Symmetry gained, tradition disputed. The collection launched with three references: the blue SPB451, this black SPB453 and the charcoal grey SPB455, a special edition for the brand's centenary with a braided Seichu strap made from recycled bottles.

SpecificationsThe numbers, in one table

IdentificationHow to tell it apart

Forty millimetres exactly, 46.4 mm lug to lug and 13 mm thick, on 20 mm lugs: one of the modern divers that sits best on a small wrist. The crystal is curved sapphire with anti-reflective coating on the inside face, and the unidirectional bezel is steel with an aluminium insert and laser-engraved markings, matt rather than the circular brushing of the previous generation.

The date window is the giveaway for this batch: small, round, between four and five, with the disc in the same colour as the dial. If the date is at three and rectangular, you are looking at an SPB143 or an earlier relative. Another quick tell: the dial reads 300 metres, not 200.

Within the collection itself, the SPB453 is the one with the black dial and bezel. The SPB451 has both in blue, and the SPB455, the special edition, in charcoal grey with gold details and a braided strap instead of a bracelet. All three share the case, the 6R55 calibre and the Diver's 300 m designation.

CollectingWhat collectors check

The first thing is to work out which side of the date war you are on. There are buyers who prefer the older SPB143 precisely because the date sits at three, and that holds the older model's price on the used market. If you genuinely do not mind, this is objectively the better watch: 100 metres more, better proportions, a recessed crown and 72 hours of reserve.

On a diver with an aluminium bezel, the insert is the part that ages. Look along the edge of the engraved markings and hunt for dents on the rim, because that is the first thing to catch a door frame. Check as well that the bezel turns anticlockwise only and with no side play, and that the crown screws down without odd resistance.

The 6R55 is rated at +25 to -15 seconds a day, a good deal tighter than the 4R calibres further down the range. It is not a certified chronometer, but a healthy example should stay inside that without drama. And if you plan to get it properly wet, ask for a pressure test: the 300 metres with the Diver's designation are real, but gaskets age the same as in any other watch.

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Close relativesThe ones it gets confused with