Chronoswiss Reference Numbers: Verify a Japanese Listing (2026)

A Chronoswiss reference number such as CH-8773-GRBK is not a random catalog code. Read in order, its four blocks tell you the collection, the case material, the design generation, and the dial/strap color — information a Japanese pre-owned listing may abbreviate, mistranslate, or simply omit. This guide decodes every block using Chronoswiss’s own current and certified pre-owned product pages, cross-checked against dozens of confirmed examples, so you can verify a listing before you commit to it.

What a Chronoswiss reference number tells you

A Chronoswiss reference number is the alphanumeric code, always starting with “CH-“, that Chronoswiss assigns to a specific model-and-dial combination. It is printed on the official product page, the warranty card, and usually the case back. Chronoswiss does not publish a single master legend explaining every letter, but the pattern is consistent enough across its current catalog and certified pre-owned (CPO) listings to decode with confidence, block by block.

This matters for a buyer sourcing from Japan because dealer listings on Japanese marketplaces often shorten the reference, drop the dial-color suffix, or describe the case material in Japanese terms that don’t map cleanly to “18ct gold” or “titanium.” Decoding the reference yourself gives you a second, independent check against what the listing claims.

Anatomy of a Chronoswiss reference number

Every current reference follows the same four-block structure:

CH – [base number][material letter] [.generation] – [color code]

  • Base number (3–4 digits): identifies the model family/collection.
  • Material letter (directly after the base number, no separator): identifies the case metal or finish.
  • Generation suffix (after a period, e.g. .1, .2, .1E): marks a specific technical revision.
  • Color code (after the final dash): a two-letter-block code for case accents, dial, and/or strap color.

Block 1: the base number tells you the collection

Chronoswiss has never published an index mapping base numbers to collections, so the table below is built from cross-referencing every reference number on the brand’s current (2026) product pages and certified pre-owned catalog. If your listing’s base number isn’t in this table, search “CH-<base number>” on chronoswiss.com directly before trusting the dealer’s model name — Chronoswiss has used dozens of base numbers across 40+ years, and this table covers the actively sold and recently discontinued lines, not the full historical catalog.

Base number Collection / model Confirmed example
8773 / 4023 / 8776 Regulator Classic CH-8773-GRBK, CH-8776-BL (Blue Steel)
8751 / 8753 / 8755 / 8756 Flying Regulator Open Gear CH-8751R-SISI (18ct gold)
8321 / 8323 Flying Regulator Jumping Hour / Sirius Flying Regulator CH-8321R-BKBK (18ct gold)
8763 Flying Regulator Night & Day CH-8763.1-BLSI2
6725 Grand Regulator / Grand Regulator Skeleton CH-6725-YEBK, CH-6725S-BKGO
1243 / 1245 Regulator Manufacture CH-1245.3-BKBK
6823 Pulse One CH-6823T-BLSI (titanium)
4221 / 4223 Pulse GMT CH-4221RM-GR (gold)
1373 / 1371 Neo Digiteur CH-1373.2-LG
1663 Q-Repeater CH-1663T-BLSI (titanium)
8023 / 8022 Small Second CH-8023.2-BLSI
5021 / 5023 Strike Two CH-5023-BLSI
6923 / 6924 / 6925 / 6926 ReSec CH-6923T.1-GRBL (titanium)
1421 / 1423 / 1426 / 1429 Delphis CH-1423T.1-BKSI (titanium)
3123 / 3128 Tourbillon CH-3123-BKBL
9343 / 9345 / 9346 / 9341 Space Timer CH-9343.2-GRBL
7542 / 7543 / 7548 Opus Chronograph / Lunar Chronograph CH-7543T.1S-BL2 (titanium)
7533 / 7553 / 7555 / 9043 / 9045 Timemaster (chronograph / GMT / skeleton) CH-9043-BK
2833 / 2853 / 2871–2893 Timemaster Automatic / Sirius / Artist / unique pieces CH-2833-OR (“Vitamin C”)
2071 Imperia CH-2071R-SI (18ct gold)
1370 Digiteur CH-1370-SI
1521 Chronoscope CH-1521R (18ct gold)
1721 / 1723 Perpetual Calendar / Sirius Perpetual Calendar CH-1723-BK
3521 / 3523 Sirius Big Date (Power Reserve) CH-3521.1R (18ct gold)
2882 Grand Pacific CH-2882.1BR-BK
8783 ReSec Classic CH-8783-BK
8123 / 8121 Sirius Retrograde Day CH-8123-CP

Block 2: the material letter right after the base number

This single letter (or short code), sitting directly against the base number with no separator, identifies the case metal or special finish. Chronoswiss leaves it blank for its default case material, which is always stainless steel on current production.

Letter Meaning Confirmed example
(none) Stainless steel CH-8773-GRBK (confirmed steel on the official spec sheet)
R 18ct rose/red gold CH-8751R-SISI, CH-2071R-SI (“Imperia Gold”), CH-8521R (“Moonphase Redgold”)
T Grade 5 titanium CH-6823T-BLSI (Pulse One, confirmed titanium case and bracelet)
K DLC black coating (can combine with R as “KR”) CH-7545K-BK-DEU, CH-7541KR-DEU
FP Full pavé (diamond-set case) CH-2873FP-BK (“Imperator full pavé”)

If a Japanese listing describes a watch as “PG” (pink gold) or “18K” but the reference number has no R, or conversely calls it “steel” when the reference carries an R, that mismatch is worth asking the seller about before you pay.

Block 3: the generation suffix after the dot

Numbers like .1, .2, or letter-number combinations like .1E and .1S mark a specific technical revision of a reference — typically a changed bracelet integration, dial construction, or movement module. Chronoswiss does not publish what each letter (E, S, M, L) stands for across its whole catalog, and the same letter does not necessarily mean the same thing on two different base numbers. Treat this block as a version tag: match the full string to an exact catalog or CPO listing rather than trying to decode the letter from first principles.

Block 4: the color code after the final dash

The block after the last dash is almost always built from two-letter color abbreviations, sometimes doubled (one for the case/bezel accent, one for the dial or strap). Chronoswiss does not publish this as a glossary either; the table below is cross-referenced from matching confirmed product names (e.g. “Blue Steel,” “Vitamin C,” “Mother of Pearl Dial”) to their reference codes.

Code Color Confirmed from
BK Black CH-8773-GRBK (grey & black dial, confirmed on spec sheet)
BL Blue CH-8776-BL (“Blue Steel,” confirmed blue dial/strap)
SI Silver CH-1370-SI (Digiteur Platinum)
GR Grey CH-8773-GRBK (confirmed grey component of a grey/black dial)
WH White CH-8145-WH (Timemaster Retrograde Day)
OR Orange CH-2833-OR (“Vitamin C”)
RE Red CH-1421.1E-BKRE (“Dracula,” black & red)
BR Brown CH-2833-BRM (“Espresso”)
GO Gold-tone dial CH-6433-GO, CH-1371R.2-GO (“Chronos”)
MP Mother-of-pearl CH-2833ST-MP (“Mother of Pearl Dial”)
LU Luminous CH-8143-LU (“Luminous Dial”)
TU / PA Turquoise / Paraiba tone CH-1423.1-BKTU, CH-3123-PABL (both named “Paraiba”)
COL Multicolor CH-3128-COL (“Psycho”), CH-1663T-COL (“Scream”)
SOL Sunburst / solar motif CH-9343.2-SOL (“Solaris”)

Two worked examples

CH-8773-GRBK — Regulator Classic, steel

8773 = Regulator Classic. No letter after the base number = stainless steel case. No generation dot, so this is the standard current version. GRBK = grey and black dial. Chronoswiss’s own spec sheet confirms all four: stainless steel, 41mm, grey/black dial, automatic Caliber C.295.

CH-8521R — Sirius Moonphase, rose gold

8521 sits in the Sirius Retrograde/Moonphase range. R = 18ct rose gold, which the product’s own name (“Moonphase Redgold”) confirms independently of the letter. No color block is listed in the certified pre-owned catalog entry for this reference, which is common on older or limited references where Chronoswiss’s archive simply lists the base code.

Cross-check the caliber on the caseback

A Chronoswiss reference number names the case and dial, not the movement, but reference and caliber families line up closely enough to use as a second check. Ask for a caseback photo and match the engraved caliber number against the family below.

Caliber family Base movement Used in
C.121–C.127 (in-house modular, since 1991) Developed from the Enicar Cal. 165 base Regulateur, Tora (C.123), minute repeater (C.126), Sirius Perpetual Calendar (C.127)
C.28x / C.29x ETA 2892-A2 / ETA 2895-2 automatic, with a Chronoswiss-designed regulator or jumping-hour module Regulator Classic (C.295), Flying Regulator Jumping Hour (C.283), Flying Regulator Open Gear (C.299)
C.74x / C.75x ETA/Valjoux 7750 chronograph Timemaster Chronograph, Timemaster Chronograph GMT
C.6001 New in-house caliber co-developed with La Joux-Perret Pulse One (2025), 4Hz, 55-hour power reserve

If a listing claims a Regulator Classic (base number 8773, which should carry a C.295) but the caseback shows a chronograph caliber in the C.74x/C.75x range, the case and movement have been mismatched — either mislabeled or swapped — and that is a reason to ask more questions before paying, not a reason to assume fraud outright.

What Chronoswiss does not publish

Be clear-eyed about the limits of this decoder, the same way you would with any brand that keeps its back-office records private:

  • No public reference-number legend. Everything above is derived from cross-referencing confirmed product pages, not copied from an official key, because Chronoswiss has not published one.
  • No public serial-number lookup. Chronoswiss does not offer a website tool to look up a case or movement serial number and get a production year. Collectors on independent watch forums report that the only route is emailing Chronoswiss (or Chronoswiss North America) directly with the serial number.
  • Case numbers are batch numbers, not date stamps. Chronoswiss cases are produced in batches, so a case number can run a year or two ahead of or behind the watch’s actual assembly date.

This is current as of October 2026; if Chronoswiss publishes a serial lookup or reference index in the future, treat any article (including this one) that predates that change as out of date on this specific point.

How to verify a Japanese listing in four checks

Check 1: does the reference exist

Search the exact reference string on chronoswiss.com’s current catalog and its certified pre-owned section. If it doesn’t appear in either and the listing doesn’t explain why (very old piece, true limited edition), ask the seller for a photo of the original warranty card, which repeats the reference number.

Check 2: does the material letter match the claim

Compare the R/T/K/FP letter (or its absence) against what the dealer states in Japanese (18金/K18 for gold, チタン for titanium, ステンレス for steel). A reference with no material letter described as “18K” is the single most common mismatch to catch.

Check 3: does the caliber match the family

Ask for a caseback photo. The engraved caliber number should fall in the family the base number implies (see the table above). A mismatch doesn’t prove the watch is fake, but it does mean the case and movement history need an explanation.

Check 4: does the dial in the photos match the color code

Hold the color-code block up against the actual photos. A “BL” reference with a black dial in the listing photos, or vice versa, usually means either the photos are stock images from a different configuration or the dial has been replaced.

FAQ

Does Chronoswiss have an official serial-number lookup?

No. As of October 2026, Chronoswiss does not publish a public tool to look up a case or movement serial number. Buyers who need a production year typically contact Chronoswiss directly with the serial number.

What does the “R” in a Chronoswiss reference mean?

R marks an 18ct rose (red) gold case, confirmed across multiple official references including CH-8751R-SISI and CH-2071R-SI (“Imperia Gold”). It does not appear on steel or titanium references.

Is a Chronoswiss with no letter after the base number always steel?

On every current and certified pre-owned reference checked for this guide, yes — the absence of a material letter corresponds to stainless steel. Chronoswiss has not published this as a formal rule, so treat it as a strong pattern rather than a guarantee on very old, pre-2012 pieces.

Does a Chronoswiss case number tell me the production year?

Not reliably. Case numbers are assigned in production batches and can run a year or more ahead of or behind the watch’s actual assembly date, according to collectors who have compared notes against confirmed Chronoswiss-sourced production years.

Buying a Chronoswiss from Japan

Chronoswiss is a small, family-owned manufacture (relocated from Munich to Lucerne after a 2012 ownership change), so Japan’s pre-owned market for the brand is thinner than for Rolex or Omega — but the pieces that do surface are frequently well-documented, since Japanese dealers routinely photograph the caseback, movement, and full set alongside the listing. That makes the checks above easier to run before you commit than on a marketplace that only shows a front-dial photo. If you’ve found a specific reference and want someone in Japan to inspect it, verify the caliber and case material in person, and handle the export paperwork, that’s the kind of search RYUZU WATCHES runs on commission rather than holding inventory.

Reference numbers by brand

This decoder is part of a series covering reference-number systems used by brands with little or no published documentation. See also: NOMOS Glashütte, Glashütte Original, H. Moser & Cie, Parmigiani Fleurier, Blancpain, Breguet, Chopard, Ulysse Nardin, Piaget, Girard-Perregaux, Vacheron Constantin, A. Lange & Söhne, Audemars Piguet, Patek Philippe, Zenith, Franck Muller, and Jaeger-LeCoultre.

For the authentication steps that apply across brands, see our authentication guide, and for watch terminology used throughout this series, the glossary.

Key takeaways

  • A Chronoswiss reference reads as base number (collection) + material letter (R=gold, T=titanium, K=DLC, FP=pavé, blank=steel) + generation dot + color code.
  • No letter after the base number means stainless steel on every confirmed current and CPO reference checked for this guide.
  • Chronoswiss publishes no serial-number lookup; dating an individual watch means contacting the brand directly.
  • Cross-check the caseback caliber against the reference’s implied family (C.1xx in-house modular, C.28x/C.29x ETA-based automatic, C.74x/C.75x ETA 7750 chronograph, C.6001 new in-house) before trusting a listing’s model claim.
  • Case numbers are batch numbers, not date stamps — they can be off by a year or more from the watch’s actual assembly date.

Sources

Comments

Copied title and URL