Longines 35mm manual wind, serial 6,234,559, case 21692/149,

willing2learn · 2026-06-10T10:15:05-0500

Hello everyone,

I would appreciate some help identifying and dating this Longines.

Known details:

35 mm diameter excluding crown
Manual-wind movement
Small seconds
Movement serial number: 6,234,559
Case reference: 21692
Additional case number: 149
Three-notch screw-back case

I have owned this watch for many years and know its provenance well enough that I have no reason to suspect a recase or marriage, but I would like to learn more about the watch itself.

My main questions are:

What is the movement caliber?
Approximately when was the watch produced based on the serial number?
Does the dial, handset, crown and case appear correct for the period?
Is there any information available on case reference 21692?
Is the three-notch screw-back case typical for Longines of this era?
Would a 35 mm case have been considered oversized for the period, and how uncommon would that size have been?

I have attached photographs of the dial, movement, case, case back and movement serial number.

Many thanks for any information or observations.

Radiumpassion · 2026-06-10T10:56:57-0500

Many of your questioms you will find by Google , but looks like a nice original tre tacche
with 12.68 Z movement.

willing2learn · 2026-06-10T12:37:48-0500

Radiumpassion
Many of your questioms you will find by Google , but looks like a nice original tre tacche
with 12.68 Z movement.

Thanks for your reply however google and the AI told me to come here for more answers 😀

Mark020 · 2026-06-10T12:49:35-0500

W willing2learn
Approximately when was the watch produced based on the serial number

Send Longines a mail with your pictures and the will tell you - free of charge - the day it was sold and where ;-)

But 6.23m will be end 1941, early 1942 I assume.

Most info on these type of cases can be found by searching for 'tre tacche'. I'd say that the watch is all correct

willing2learn · 2026-06-10T13:58:32-0500

Mark020
Send Longines a mail with your pictures and the will tell you - free of charge - the day it was sold and where ;-)

But 6.23m will be end 1941, early 1942 I assume.

Most info on these type of cases can be found by searching for 'tre tacche'. I'd say that the watch is all correct

Thank you for the reassurance, do you think a extract from the archives at Longines is worth it for this watch?

Mark020 · 2026-06-10T14:35:07-0500

The mail is free. If you want the same info on paper you pay for it

Longines 35mm manual wind, serial 6,234,559, case 21692/149,

willing2learn

Radiumpassion

willing2learn

Mark020

willing2learn

Mark020

Similar threads

275 euro - Vintage Longines 35mm

Vintage Eterna - Manual winding with a great dial

Vintage SS Longines ref. 6536-1 w/Breguet Numeral Dial, Cal. 19AS

KELEK 2-Register Chronograph 17j Manual Wind Valjoux 7733 Stainless

Vintage 1965 Omega - Cal. 601 Manual Wind - Serviced

Helbros Invincible skin diver - manual wind & serviced