The storyWhy this reference matters
Sinn comes from Helmut Sinn, a Luftwaffe pilot and later a racing driver, who started out selling watches to American servicemen stationed in Germany and set up his company in Frankfurt. The brand dates its founding to 1961. In 1994 he sold it to Lothar Schmidt, an engineer who had come from IWC, and it was Schmidt who brought in the catalogue of technologies, Tegiment hardening, copper-capsule dehumidifying and oil filling, that the name is known for today.
The 556 arrived at the end of 2007 as the entry-level watch. It shared an almost identical case and dial with the 656 of the day, differing in the finishing and in the sapphire back, which added a millimetre of height. The 656 left the catalogue in 2012 and the 556 was alone on that rung. In 2011 it became the 556 I, because the 556 A with Arabic numerals appeared and the two had to be told apart.
The point of the 556 is what it does not have. Worn & Wound said as much in its review: none of the technologies that made Sinn famous are here. What is here is an exceptionally well-made case, because Sinn is one of very few brands with its own case factory, SUG in Glashutte, plus two sapphire crystals and 20 bar. It is a watch that stands up on geometry and finishing alone.
SpecificationsThe numbers, in one table
| Brand | Sinn |
|---|---|
| Family | 556 |
| Reference | 556 I |
| Years made | desde 2011 |
| Calibre | Sellita SW200-1 (unidades anteriores: ETA 2824-2 top grade) |
| Movement | Automatico |
| Frequency | 28.800 alt/h (4 Hz) |
| Power reserve | Unas 38 horas |
| Complications | Fecha |
| Diameter | 38.5 mm |
| Thickness | 11 mm |
| Lug to lug | 45.7 mm |
| Lug width | 20 mm |
| Case | Acero inoxidable satinado |
| Crystal | Cristal de zafiro con antirreflejos por las dos caras; fondo de zafiro |
| Water resistance | 20 bar (200 m) |
IdentificationHow to tell it apart
Start with what confuses people most: 556 I A is not an official Sinn designation. In their naming the I and the A are mutually exclusive, I being bar markers and A Arabic numerals, so they cannot appear together on this model. The combination does exist in the 104 family, where the 104 St Sa I A is the anthracite-dial version with bars. In the 556 series the official catalogue runs 556 I, 556 A, 556 I RS, 556 A RS, 556 I B, 556 I M and the mother-of-pearl versions. When somebody advertises a 556 I A, it is almost always a badly typed 556 I or the 2016 Anniversary edition, anthracite dial, no date, limited to 1,000 pieces.
Telling the I from the A takes a second. The 556 I has a glossy black dial, a deeper black than usual precisely because it is not matt, and bars only: large rectangles for the hours and fine strokes for the minutes, with no double marker at twelve and no other hierarchy. The date sits at three, with the marker cut away to make room. The 556 A has 12, 3, 6 and 9 in numerals on a matt dial and the date between four and five, with the digits rotated so they read upright.
Measurements are 38.5 mm across, 45.7 lug to lug, 11 tall and 20 mm between the lugs, with a screw-down crown between guards. And there is a quick way to date a used example: look through the sapphire back. An ETA 2824-2 with a gilt rotor means an early one. Current pieces use the Sellita SW200-1.
CollectingWhat collectors check
The case finish is what Sinn calls satinised, halfway between polished and brushed. It is handsome and it is fragile: any refinishing turns it into something else, and being untreated steel with no Tegiment, it marks perfectly readily. Decide before you buy whether this is going to be your everyday watch or your smart one, because both are legitimate and they lead to very different conditions.
The lume is weak even from new. Worn & Wound flagged it in their review, so it is not a fault in the example you are looking at. What does need checking is the screw-down crown and its gasket, because the watch is rated to 20 bar and plenty of 556s have ended up in a swimming pool on that basis. Check the date change around midnight too, and that the seconds hand stops when you pull the crown.
On the market, Sinn's H-link bracelet adds a good deal to the total and buying one separately afterwards is expensive, so a 556 I with the original bracelet is usually worth the difference. Coloured dials and limited runs trade more briskly, but the standard black is the one that never wants for a buyer. It is the 556 people mean when they say they want a Sinn.
Common questionsWhat people ask us about this reference
Does the Sinn 556 I A exist?
Not as an official reference. In Sinn's naming, I means bar markers and A means Arabic numerals, so on the 556 they are mutually exclusive. The confusion usually comes from the 2016 556 Anniversary, which had an anthracite dial, or from mixing up the 556 I and the 556 A.
556 I or 556 A?
The I is the discreet one: bars, a glossy black dial and the date at three. The A is the more tool-like: numerals at 12, 3, 6 and 9, a matt dial and the date between four and five with the digits upright. Same case, same movement.
Which movement is in the Sinn 556 I?
Current pieces use the Sellita SW200-1 automatic, running at 28,800 vibrations per hour with around 38 hours of reserve. Earlier ones had an ETA 2824-2 in top grade.
How big is the Sinn 556?
38.5 mm across, 45.7 mm lug to lug, 11 mm tall and 20 mm between the lugs, rated to 200 metres.
Does it have Sinn's technologies?
No. The 556 has no Tegiment, no dehumidifying capsule and no oil filling. What it brings is the case, made in Sinn's own factory in Glashutte, two sapphire crystals and 20 bar.
Keep readingWhere to go from here
Close relativesThe ones it gets confused with
See Sinn 556 at auction now → What is up for sale on Catawiki today. Read the page above before you bid: half the mistakes come from not checking the reference.Confidence: media — this page was checked against the sources below. If a detail looks wrong to you, write to us and we will fix it.