A. Lange & Söhne Reference Numbers: Verify a Japanese Listing (2026)

An A. Lange & Söhne reference number is six digits written as XXX.XXX. The first three digits identify the model line and series; the last three identify the exact execution — case metal and dial. This guide shows how to read a Lange reference number, why the metal is not spelled out in a letter code the way it is on a Rolex, and how to check the reference against a Japanese listing before you commit to buying.

If you are buying a pre-owned or grey-market Lange from Japan, the six-digit reference is the single most useful string in the listing. Matched to the catalog, it tells you the model, the metal, the dial and roughly the generation. Left vague (“Lange 1, pink gold”) it tells you almost nothing. This is written for buyers outside Japan who cannot handle the watch first.

The 30-second version

• Format: six digits, XXX.XXX (three digits, a dot, three digits). Example: 191.032.
• First three digits = model line + series/movement generation (191 = the 2015-onward Lange 1).
• Last three digits = the exact execution: case metal and dial. In 191.032, the .032 execution is 18k pink gold with a silver dial.
• The metal is not a readable letter. Unlike Rolex material suffixes or Audemars Piguet two-letter codes, you decode a Lange’s metal by matching the full six digits to the catalog, not by reading one character.
• Reference ≠ serial. The reference is the catalog number; the serial (and the movement number) is unique to the individual watch and is what dates it.
• English searchers often type the brand as “A. Lange & Sohne” without the umlaut; it is the same reference number system either way.

How an A. Lange & Söhne reference number is built

A modern Lange reference is a six-digit number split by a dot into two halves of three digits each. Both halves carry meaning, and reading them in order is the fastest way to confirm what a listing is actually offering.

The six-digit format: XXX.XXX

Every current-production reference follows the same shape: 191.032, 403.035, 363.179. There is no letter prefix for the metal and no separate “case code” you need to assemble. The reference is one number; treat it as one number.

First three digits = the model line and series

The opening three digits tell you the collection and, within a collection, the series or movement generation. The Lange 1, for example, moved from the 101 series (original movement) to the 191 series when the model was redesigned. A quick map of the common prefixes:

Reference prefix	Model line	Example reference
101 / 191	Lange 1 (original / 2015-onward series)	101.001, 191.032
201 / 219	Saxonia (incl. Saxonia Thin)	201.027
4xx (e.g. 414)	1815 collection	414.026
403 / 405 / 410	Datograph family	403.035, 410.038
140 / 142	Zeitwerk	—
363	Odysseus	363.179

Prefixes are a strong signal, not a guarantee — Lange has used related numbers across variants, so always finish by matching the full six digits, not just the first three.

Last three digits = the exact execution (metal + dial)

The three digits after the dot pin down the precise version: case metal and dial colour. For reference 191.032, the .032 execution is 18k pink gold with a solid-silver dial. Change the metal or dial and the last three digits change with it, even though the model line stays the same.

Why the metal is not spelled out in the reference

This is the point that trips up buyers coming from other brands. On a Rolex, the material is a readable suffix in the reference; on an Audemars Piguet, a two-letter code near the end tells you the case metal. On a Lange, there is no such letter. The metal is baked into the last three digits, and you learn it only by matching the whole reference to the catalog.

Useful side effect: Lange has tended to keep an execution code tied to the same metal across a model’s life, so the same suffix reappears on a later series in the same metal. The pattern below holds for the Lange 1 across its 101 and 191 series:

Execution suffix	Case metal	101 series	191 series
.021	Yellow gold	101.021	191.021
.025	Platinum	101.025 (“Stealth”, silver dial)	191.025
.032	Pink gold (silver dial)	101.032	191.032
.039	White gold	101.039	191.039

So if a listing quotes 191.032 and calls the watch “white gold,” something is wrong: .032 is pink gold. That single cross-check catches copy-paste errors and, occasionally, worse.

Reference numbers by model line, with real examples

Below are concrete references you will actually meet on the Japanese market, grouped by line. Use them to sanity-check what a listing claims.

Lange 1 (101 and 191 series)

The 101 series is the original Lange 1, introduced in 1994 with caliber L901.0. The 191 series is the redesigned Lange 1 from 2015, built on caliber L121.1, with a slimmer bezel and a matte-polished mid-case. Generation counts vary between sources, so anchor on the caliber and the launch year rather than on “Gen 2 vs Gen 3” labels.

Notable references: 101.001 (yellow gold, champagne dial), 101.025 “Stealth” (white gold, silver dial), 101.035 “Darth” (platinum, black dial), and on the modern side 191.032 (pink gold) and 191.039 (white gold). The rarity to know is 101.026, the only stainless-steel Lange 1 — only an estimated 20–30 were made around 1998–99. If a listing claims a steel Lange 1, that reference and its rarity are the first things to verify.

Saxonia and 1815

Saxonia is the contemporary, pared-back dress line; the Saxonia Thin (roughly 37–40 mm) is its purest expression, with references such as 201.027. The 1815 line draws on 19th-century pocket-watch heritage and carries 4xx references — for example, the 1815 Chronograph “Boutique Edition” 414.026 in white gold.

Datograph (403, 405, 410)

The Datograph flyback chronograph arrived in 1999 with references such as 403.035 (platinum, black dial) and 403.031 (rose gold, black dial). The later Datograph Up/Down (41 mm) uses 405 references, including 2024 limited editions like 405.028 (white gold, blue dial). The Datograph Perpetual sits in the 410 range, e.g. 410.038 in white gold. A trailing letter appears on some special editions (for example a hand-engraved 405.048F); treat any letter as part of the full reference and confirm what it denotes against the catalog rather than guessing.

Zeitwerk and Odysseus

The Zeitwerk, with its jumping mechanical digital display, carries 140/142 references. The Odysseus — Lange’s sports line launched in 2019 — uses the 363 prefix: 363.179 is the original stainless-steel model, and 363.117 (2022) is a titanium limited edition of 250 pieces. Steel and titanium are unusual for Lange, so an Odysseus reference is worth confirming precisely because the material tells you which variant you are looking at.

Honey gold and other alloys

Lange also uses honey gold, a proprietary pale-yellow alloy reserved mainly for limited editions (seen on references such as 101.050). Cases otherwise run in yellow, pink and white gold and platinum. Movements are made of untreated German silver with hand-engraved balance cocks — each engraving is slightly different, which is both a finishing signature and a quiet authenticity cue.

Reference number vs serial and movement number

The reference is the catalog number shared by every watch of that execution. The serial number and the movement number are unique to the individual piece and are what date it. They are not interchangeable, and a listing should give you both the reference and a serial you can see in a photo.

The serial is typically engraved on the caseback or the case side, often alongside the Lange logo; placement varies by model and year. To determine a watch’s exact age, Lange itself works from the reference number, the serial or case number, or the original papers and an archive extract. If none of those are present, be cautious about any firm claim of year.

Common red flags on a remote purchase are a serial that does not match the model, an oddly placed or poorly cut engraving, or no serial at all. None of these is proof of a fake on its own, but each is a reason to ask for more photos. The same discipline applies to the case itself — see our guide to reading over-polished signs from a Japanese listing.

How to verify a Lange reference against a Japanese listing

You do not need the watch in hand to do most of this. Work through the reference first, then the individual-watch details.

• Get the full six-digit reference. “Lange 1 pink gold” is not enough; ask for the exact XXX.XXX. Then match all six digits to the catalog and confirm the metal and dial agree with the photos.
• Cross-check the execution suffix against the stated metal. If the last three digits say platinum and the listing says gold, resolve the contradiction before paying.
• Confirm the generation via caliber and case, not the label. A 101 and a 191 Lange 1 look similar in a thumbnail; the caliber (L901.0 vs L121.1) and bezel/mid-case finishing separate them.
• Ask for a caseback photo showing the serial, and a movement photo showing the hand-engraved balance cock. These belong to the individual watch, not the catalog.
• Ask what papers exist: the “History of Your Watch” booklet, the guarantee card and its date, and any service invoices. Papers do not make a watch genuine, but their absence changes the price you should pay.

Because Lange’s reference does not announce the metal, this brand rewards buyers who insist on the full six digits and a legible caseback. The same logic underpins our sister decoders for Patek Philippe and Audemars Piguet, where the encoding rules differ but the verify-first habit is identical. If you would rather have the watch inspected in Japan before you commit, RYUZU WATCHES can do that on your behalf (see our authentication process).

Papers, guarantee and proof of origin

Lange’s guarantee terms matter to a cross-border buyer because they decide what you are actually inheriting. The figures below are from A. Lange & Söhne’s official service pages and are current as of September 2026; confirm them for your market before you rely on them.

• Two-year guarantee from the date of purchase on every Lange watch, covering material and manufacturing defects.
• A third year is available if the watch was obtained from a boutique and successfully registered on Lange’s website — an owner-specific step a later buyer may not have completed.
• After an overhaul or repair, Lange grants a further 24-month guarantee on the parts affected by the work.
• Recommended overhaul interval: every five to seven years.
• Proof of origin: on request, Lange’s service team can provide a proof-of-origin document for timepieces manufactured after 1990 — useful when a grey-market watch arrives without full papers.
• No guarantee applies if Lange suspects the watch is lost or stolen, including where it appears on a lost-and-stolen database.

The guarantee seal or card sits on the first page of the “History of Your Watch” booklet that ships with the watch. For a pre-owned piece, read the guarantee date against the reference and serial, and treat service invoices as part of the provenance — our guide on verifying service history from a Japanese listing covers what to ask a seller to photograph.

Buying a Lange from Japan: what actually changes

Japan is a deep market for high-end dress watches, and A. Lange & Söhne circulates there both through the authorised network and on the pre-owned and grey market. Two distinctions decide how you read a listing.

Authentic is not the same as authorised. A grey-market Lange is a genuine watch that did not pass through the brand’s authorised retail network. It can be entirely authentic and still lack authorised-dealer paperwork. Do not accept “100% genuine, authorised” unless both are actually true; describe what you can verify and no more.

Condition language needs evidence. “Mint” means little on its own. Ask what supports it: the caseback engraving sharpness, the balance-cock finishing, the state of the hallmarks, and whether the case has been polished. For decoding the wider set of reference systems you may meet alongside a Lange, our Rolex reference guide and Omega reference guide use the same verify-first approach.

Frequently asked questions

What does an A. Lange & Söhne reference number look like?

It is six digits in the form XXX.XXX, such as 191.032. The first three digits give the model line and series; the last three give the exact metal-and-dial execution.

How do I tell the metal from a Lange reference number?

You match the full six digits to the catalog. Lange does not put a readable metal letter in the reference, unlike Rolex or Audemars Piguet, so the last three digits — not a single character — carry the metal.

Is the reference number the same as the serial number?

No. The reference is the catalog number shared by all watches of that execution. The serial and movement numbers are unique to the individual watch and are what date it.

Can Lange confirm a watch is genuine?

On request, Lange’s service team can issue a proof-of-origin document for timepieces manufactured after 1990. This is helpful when a grey-market watch lacks its full papers.

How often should a Lange be serviced?

Lange recommends an overhaul every five to seven years. A completed service comes with a fresh 24-month guarantee on the parts affected by the work.

Key takeaways

• A Lange reference is six digits, XXX.XXX: model line + series first, exact execution (metal + dial) last.
• The metal is not a readable letter — match the whole reference to the catalog.
• Confirm the execution suffix agrees with the stated metal; contradictions are a red flag.
• Get the reference, a caseback serial photo, and the “History of Your Watch” booklet before you buy remotely.
• Guarantee runs two years from purchase (a third with boutique registration); overhaul every five to seven years; proof of origin available for post-1990 watches.

If you are looking for a specific A. Lange & Söhne reference, RYUZU WATCHES searches the Japanese market on your behalf and inspects the watch before you commit. Send us the reference you are after.

Reference numbers by brand

Part of our series on decoding reference numbers to verify a Japanese listing:

• Patek Philippe reference numbers
• Audemars Piguet reference numbers
• Rolex reference numbers
• Omega reference numbers
• Jaeger-LeCoultre reference numbers
• Cartier reference numbers
• Zenith reference numbers

This article is for general guidance and reflects the model and service information available as of September 2026. Reference details, guarantee terms and service policies can change; confirm current specifics with A. Lange & Söhne for your market before buying.