Featured inventory photo: Jaeger-LeCoultre Master Control Calendar Q4148420 from Pucks & Timepieces. The pictured watch is a different Jaeger-LeCoultre calendar model, not the Master Ultra Thin Moon discussed in this guide.
The JLC Master Ultra Thin Moon is worth considering when you want a dress watch with something to discover beyond the time. As a concrete example, the steel Q1368460 combines a 39 mm case with automatic winding, a date display and a moonphase complication (Jaeger-LeCoultre’s official specifications).
My recommendation is to approach a pre-owned example as a specific watch, not just a familiar model name. Confirm the reference, assess its condition and understand the setting routine before deciding whether it belongs in your collection.
Why consider the Master Ultra Thin Moon?
To my eye, the appeal is balance: enough visual detail to reward a closer look without asking the whole dial to compete for attention. It is a useful direction to explore if your collection already leans heavily toward sports watches and you want something with a different character.
Before shopping, decide when you will actually wear it. If the answer is only an imagined formal occasion years away, consider whether a different configuration would bring you more enjoyment now.
A reference-specific starting point
For Q1368460, JLC lists a 39 mm stainless-steel case, 9.3 mm thickness, 5-bar water resistance and the automatic calibre 925 with a 70-hour power reserve (official Q1368460 product page). These numbers are a benchmark for that reference, not a promise that every watch carrying the Master Ultra Thin Moon name shares the same specifications.
- Movement: JLC specifies calibre 925, automatic winding and a frequency of 28,800 vibrations per hour, or 4 Hz, for Q1368460 (Jaeger-LeCoultre).
- Displays: The stated functions include hours, minutes, seconds, moonphase and a hand-indicated date (Jaeger-LeCoultre).
- Finishing: JLC describes beveling, Côtes de Genève and blued screws on the movement (Jaeger-LeCoultre).
For any other reference or production period, ask for the corresponding manufacturer documentation. Do not let a seller substitute a current catalogue page for the specifications of an older watch without checking the match.
Evaluate the watch, not just the dial photograph
I would ask for front, side and rear photographs in even lighting, plus close-ups of the lugs, bezel, crown and buckle. The goal is a clear view of the actual condition, not a single flattering image.
- Case shape: Ask about polishing and request photographs that show the case edges clearly.
- Dial and hands: Request disclosure of marks, discoloration or replaced components. Ask for additional images if reflections obscure the view.
- Functions: Have the seller demonstrate winding, time setting, date operation and moonphase adjustment using the correct procedure.
- Strap and clasp: Confirm their condition, fit and originality. Include any replacement you would want in your purchase budget.
- Service documentation: Ask what work was done, by whom and when. If the history is unknown, obtain a service estimate before treating the asking price as the full cost.
A beautiful dial should not distract you from unanswered questions elsewhere. If you cannot establish the condition with confidence, pause and request a qualified inspection.
Think through the ownership routine
Ask for the correct operating instructions and a demonstration before adjusting the calendar or moonphase yourself. I would avoid generic online shortcuts when the reference-specific instructions are available.
Also decide whether this will be a regular wearer or a watch you bring out occasionally. If resetting displays sounds like a chore rather than part of the enjoyment, make that a real factor in the decision.
For a different design approach, our Reverso Monoface vs Duoface guide offers another way to frame a JLC purchase. Try both shapes if possible rather than treating photographs as a substitute for wrist fit.
Frequently asked questions
Does every Master Ultra Thin Moon have a 70-hour reserve?
The official Q1368460 page lists 70 hours (Jaeger-LeCoultre). Do not apply that figure to another reference or an older example without confirming its documentation.
Should I prioritize box and papers over condition?
I would not let a complete accessory set override concerns about the watch itself. Request both a clear condition assessment and an exact list of what is included, then decide what each is worth to you.
Is it the right first dress watch?
It belongs on the shortlist if you like its design and are comfortable with the ownership routine. My preference is to choose a watch you can picture wearing now, not one that simply fills a category in a collection checklist.
Build a focused shortlist
Start with your preferred metal, dial, dimensions and all-in budget. Ask Pucks & Timepieces to help source a Master Ultra Thin Moon, or review our sell-or-trade options if another watch may be part of the move.
