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The Encyclopedia of Horology

Wristwatch · Flyback chronograph wristwatch

Longines Ref. 5161 'Sommatore' Flyback Chronograph Wristwatch

Partially verified

This lot features a Longines reference 5161 stainless steel manual-wind flyback chronograph wristwatch, nicknamed 'Sommatore' or 'Doppia Lancetta', dating to circa 1946. It is powered by the 18-jewel Longines calibre 13ZN-12, notable for its central minute recorder operating in synchrony with the central chronograph seconds hand. The 39.5 mm round case features rectangular pushers, a snap-on back, and is attached to a textured black leather strap. The silvered dial displays painted Arabic numerals, an outer tachymeter and minute track, a running seconds subsidiary dial at 9 o'clock, and a 12-hour subdial counter at 3 o'clock.

Longines reference 5161 'Sommatore' stainless steel flyback chronograph wristwatch, circa 1946.
Longines reference 5161 'Sommatore' stainless steel flyback chronograph wristwatch, circa 1946. — Adam's / Invaluable. Rights pending — permission not yet requested. Original source

Catalogue identity

Source
www.invaluable.com
Category
Wristwatch · Flyback chronograph wristwatch
Maker / attribution
Longines
Reference
5161
Catalogue / lot identifier
56
Source-reported date
circa 1946
Country
Switzerland

Source-reported attribution and specifications are not independent authentication. A listing does not establish present ownership, current display, availability or permission to reproduce.

Object description

Case and External Architecture

The reference 5161 is constructed with a 39.5 mm stainless steel round case, featuring a snap-on case back. Inner case back markings are identified as EFCo Longines with reference 5161 and order number 23021.

The watch is fitted with a black leather strap and the original Longines pin buckle. Condition reports describe the case as having sharp lugs with light surface wear.

Evidence for this section
  • “Stainless steel round case, snap-on back, inner caseback stamped EFCo Longines with reference 5161 and order number 23021.”
  • “Diameter: 39.5 mm”
  • “Case: Stainless steel case in outstanding state of preservation, sharp lugs, light surface wear only.”
  • “Bracelet/Strap: Black leather strap with original Longines pin buckle.”

Dial Configuration

The silvered dial includes an outer tachymeter and minute track, with painted Arabic numerals. Timekeeping and timing functions are managed via subsidiary seconds at 9 o'clock, a 12-hour counter at 3 o'clock, and central chronograph hands. The latter consist of a blued central chronograph seconds hand and a polished steel central chronograph minute recorder.

The condition report notes that the dial was refreshed during service but specifies it was not reprinted.

Evidence for this section
  • “Dial: Silvered dial with outer tachymeter and minute scales, Arabic numerals, blued central chronograph seconds hand and polished steel central chronograph minutes hand (Sommatore), subsidiary seconds at 9 o’clock and 12-hour counter at 3 o’clock”
  • “Dial: Attractive silvered dial, refreshed during service but not reprinted”

Movement and Specifications

The watch is powered by an 18-jewel manual-wind Longines calibre 13ZN-12. This movement features a flyback chronograph mechanism with a central minute recorder. The calibre and case are signed.

The movement was serviced by Longines in April 2025. It was recorded as running at the time of cataloguing, though the auction source notes it was not tested for accuracy.

Evidence for this section
  • “Calibre: Manual-wind Longines calibre 13ZN-12, flyback chronograph with central minute recorder (“double flyback” seconds & minutes), 18 jewels, signed.”
  • “freshly serviced by Longines (April 2025), running at the time of cataloguing; not tested for accuracy.”

Open research questions

  • Verify the distinction between a 'refreshed' dial and original factory finishes.
  • Confirm the technical specifications of the 13ZN-12 central minute recording mechanism.

Source evidence

Recorded claims and source quotations for Longines Ref. 5161 'Sommatore' Flyback Chronograph Wristwatch
FieldSource-reported valueSource quotation
Reference5161“LONGINES REF. 5161, SOMMATORE CHRONOGRAPH, STAINLESS STEEL”
Calibre13ZN-12“Manual-wind Longines calibre 13ZN-12, flyback chronograph with central minute recorder”
Case Diameter39.5 mm“Diameter: 39.5 mm”
Order Number23021“inner caseback stamped EFCo Longines with reference 5161 and order number 23021.”
Delivery Year1946“Year: 1946 (delivered to Longines’ agent Weil in Chile, according to Extract from the Archives)”
Delivery Date1946“Year: 1946 (delivered to Longines’ agent Weil in Chile, according to Extract from the Archives)”
Production Estimate250“production of the 13ZN-12 Sommatore ran only from 1945 to 1947, with an estimated 250 examples in steel.”

Visible details

  • Silvered dial with two sub-dials situated at 3 and 9 o'clock
  • Four central hands including blued chronograph seconds and polished steel chronograph minutes
  • Fitted to a textured black leather strap with black stitching

Research qualifications

  • Condition report notes the dial was refreshed during service, though not reprinted
  • Movement and inner case back are not shown in the provided photograph

Photograph identity and source facts were screened before import; rights clearance remains pending.

Consulted source

Sold at Auction: LONGINES REF. 5161, SOMMATORE CHRONOGRAPH, STAINLESS STEEL An extremely rare and incredibly well preserved stainless steel manual-wind “Sommatore” flyback chronograph wristwatch with central minute recorder, circa 1946. Year: 1946 (delivered t

Reviewed 2026-10-26 · Record 100850da80

Terms in this record

Glossary explanations for terms named in this object’s record.

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