Very fine and rare platinum, keyless “shutter” pocket watch with concealed dial Geneva, NO. 87866, made for Caldwell & Co, circa 1920.

Pressing the spring-loaded winding crown opens the shutters, revealing the dial. Pulling out the crown to set the watch also opens the shutters. The shutter mechanism was patented by Jaeger in 1910, in both France and Switzerland (FR412821, CH50854), and was used mostly on Cartier watches.

Functions: Hours, minutes
Signed: Dial, case, movement
Dimensions: 44 mm ∅
Case: Three-part, bassine, snap-on fit, front with two shutters which bydepressing the push piece at the top of the crown open revealing the dial, back engraved with monogram
Dial: Silvered, matte, with black Arabic hours, outer minutes track
Hands: Blued steel Breguet
Movement: 37.5 mm, rhodium-plated, 18 jewels, straight-line lever escapement, bimetallic compensation balance, eight adjustments, blued steel flat balance spring

Case: Very good
Dial: Very good, some patina
Hands: Good, one repaired
Movement: Good, center jewel replaced