Reference:1831: Difference between revisions

|modified_time=2026-06-29T01:18:21Z

<small>[[Reference:day-date|Day-Date]] → '''1831'''</small>

The 1831 is the platinum "Emperor", the rarest and most exotic of the vintage Day-Dates. It abandons the round President case for an angular, integrated-bracelet platinum case, the one Rolex used on the 1530 and 1630 and carried into the Oysterquartz, and renders it in solid platinum with a diamond bezel. It was never a catalogue reference in the ordinary sense. Around eight were built as a special order for the household of the Shah of Iran, each with a different diamond-set dial, and a ninth, carrying the Omani Khanjar, surfaced later. It is the Day-Date at its most imperial, and the hardest of all of them to find.

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The 1831 is barely a Day-Date in the usual sense. Where the 1803 and its siblings are round 36mm Presidents, the 1831 takes the angular, integrated-bracelet case of the 1530 and 1630, the same architecture Rolex would carry into the Oysterquartz, and builds it in solid platinum with a factory diamond bezel. The case is the point: it is not a President, and it does not wear like one. The watch reads as a piece of platinum sculpture with a Day-Date dial set into it.

It sits apart from the other rare platinum Day-Dates. The platinum Arabic and Khanjar examples of the 1802, 1803 and gem-set 1804 keep the round President case; the 1831 alone moves to the integrated case. That, plus its tiny numbered production, is why specialists treat it as a reference of its own rather than a variant. Some catalogues file it under "Oysterquartz" because of the case shape, but the 1831 is mechanical, not quartz: it runs an automatic 1556-family movement.

The 1831 was built to order in tiny numbers, never a catalogue model. The numbered series, generally cited as eight pieces, was built for the household of the Shah of Iran around 1977, each example carrying a different diamond-set dial. The watches are numbered between the lugs, and documented examples include No. 001, No. 004 and No. 5. A ninth platinum 1831, carrying the Omani Khanjar emblem rather than a plain or Stella dial, surfaced at Sotheby's in 2018; its case serial sits alongside the Iranian pieces, extending the known count to nine and crossing the series into Oman. Documented case serials cluster tightly, from around 5,055,000 to 5,087,000, consistent with a single small production run. No standard catalogue presence exists for the reference, which is why so much of what is known comes from the auction record.

The 1831 runs a mechanical automatic movement, not the quartz its case shape suggests. The caliber is recorded as the 1556 in the Sotheby's catalogue and as a purpose-built 1566 in most other catalogues and in the specialist literature, a 26-jewel, 19,800 vph movement from the same 1500 family as the 1803's. As with every 4-digit Day-Date it has no quickset, and it dates to the hacking era after 1972. The case is the unusual part; the movement is conventional Rolex mechanical for the period. The [[Reference:Movements]] page holds the caliber lineage, and the [[Reference:1803|1803]] entry covers the 1555-to-1556 family in detail.

 

Each of the numbered 1831s carries a different diamond-set dial, which is part of the appeal of the series. Documented dials include a light-blue sunburst with round-brilliant and baguette diamond markers, a burgundy Stella lacquer with oversized diamond markers, and plain silvered grounds with diamond-set numerals. The markers sit closer to the centre of the dial than on a standard Day-Date, a layout cue of the platinum special orders. The Omani "Khanjar No. 9" carries a silvered sunburst dial with diamond markers and the red crossed-daggers emblem of the Sultanate at six o'clock. Because the run is so small and each dial is distinct, the dial is effectively the identity of each individual watch rather than a catalogue option.

The case is the 1831's whole reason for being. It is solid platinum in the angular, integrated-bracelet idiom of the 1530 and 1630, sharp-faceted and brushed, around 40mm and substantially heavier than a President, with one documented example weighing about 290 grams all in. The bezel is factory diamond-set, round brilliants with baguettes at six and nine on the documented examples, and the crystal is acrylic over a Twinlock screw-down crown. The bracelet is integrated, built into the case rather than fitted with end-links, so the watch cannot take a standard President. Some catalogues describe the case as the "Oysterquartz" case because Rolex used the same architecture for the quartz line; on the 1831 it houses a mechanical movement.

The 1831's platinum bracelet is integral to the case, in the King Midas and Oysterquartz idiom, and cannot take a removable President. That integration is much of why the watch wears so differently from a round Day-Date. Where the original bracelet survives it is part of the watch's value; the Omani "Khanjar No. 9" had its platinum bracelet removed and sold before sale, and it appears on a strap. The cross-family bracelet detail sits on [[Reference:Bracelets]].

The core of the reference is a numbered set, generally cited as eight platinum examples, built for the household of the Shah of Iran around 1977. Each carries a different diamond-set dial, from the light-blue sunburst to the burgundy and other Stella lacquers, and each is numbered between the lugs. The watches recirculate through the major auction houses, where the same numbered examples reappear across sales, consistent with so small a production.

 

A ninth platinum 1831 surfaced at Sotheby's in Geneva in 2018, carrying the red Omani Khanjar emblem. Sotheby's presented it as extending the believed run of eight to nine, the only example made for the Sultanate of Oman, with a serial number sitting alongside the Iranian pieces. Per the consigning owner, and not independently confirmed by the house, the watch may have been gifted by Sultan Qaboos to the first premier of Djibouti at that country's independence in 1977. It is the single most storied 1831.

The 1831 trades as a blue-chip rarity despite its tiny production, and the same handful of watches recirculate through the major houses. Christie's sold No. 004 in Geneva in 2011 for CHF 147,000. Antiquorum sold the burgundy Stella No. 5 in 2013 for CHF 206,500, and Phillips sold the same watch again in 2015 for CHF 305,000, the highest documented result for the reference. The light-blue No. 001 has come to sale three times, identified across all three by its case number 5,055,759 and movement number DD336356. Antiquorum sold it in Geneva in 2014 for CHF 165,750, Phillips in Hong Kong in 2016 for HK$1,750,000, and Phillips in Geneva again in 2021 for CHF 289,800. The Omani "Khanjar No. 9" sold at Sotheby's in 2018 with the result not publicly disclosed. The trajectory across the 2010s is steadily upward, and an original, unpolished platinum case with its integrated bracelet is the value driver.

* [[Reference:1803|Day-Date 1803]] — Fluted President (1960–1977)

* [[Reference:1804|Day-Date 1804]]

* [[Reference:1806|Day-Date 1806]]

* [[Reference:1807|Day-Date 1807]]

* [[Reference:1811|Day-Date 1811]]

* [[Reference:6510|Day-Date 6510]] — 1956–1957

==Sources==