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Decalogue Rega watch оn the background of old papyrus

Jewish way of telling the time

The “Decalogue Rega” is the flagship and most sophisticated model of the “Decalogue” collection. It is the only wristwatch in the world which measures time in the traditional Jewish way, including small units such as heleks (1/18 minute), and regaim (singular: rega) (1/76 helek, or around 0.044 seconds). Heleks and regaim have been used by Jewish astronomers since ancient times, and along with the days and the hours they are the basis for measuring time in the Jewish lunar calendar.

The rega hand is one of the fastest in watch mechanics, making a revolution once every 7.2 seconds. Konstantin Chaykin mounted this on the back of the movement, where there is a special wheel drive. Besides this, the back of the movement is also decorated with a miniature figure of a heraldic lion, a symbol of the city of Jerusalem.

 The reverse movement system of the minute (pointer) wheels in the Decalogue Rega watch

Watch features


  • Dial assembly in the Decalogue Rega watch
    installation of arrows in theDecalogue Rega watch
    Case back installation for the Decalogue Rega watch
    Decalogue Rega watch back view of the mechanism
    Golden lion on the back of the movement Decalogue Rega watch
    Tools and disassembled Decalogue Rega watch

Сase back

Watch back sapphire crystal with antireflective coating
Decalogue Rega watch  photo of case back


The calibre K.01-1 PS of the “Decalogue Rega” watch was developed by Konstantin Chaykin and is equipped with a reverse time indication system with anti-clockwise hand rotation, a helek indicator on the dial and a rega indicator on the reverse side of the movement. The movement was made entirely at the Konstantin Chaykin manufactory and is made according to the standards of haute horlogerie. Components finished using classical techniques: striped andperlage; fine longitudinal and circular grindings; manual chamfering, polishing; polished screw holes, pins and jewels; spherical polishing of the axel tips; and galvanized plating of rhodium and gilding. A distinctive feature of the movement is the use of four gold ouches, and placed on the back of the movement is a miniature golden figure of a heraldic lion, the symbol of Jerusalem, and a branded regulator(a device developed by Konstantin Chaykin to fine tune the effective length of the spring).

Caliber: K.01-1 PS with hand winding by Konstantin Chaykin manufacture

Accuracy: +/-15 seconds per day

Power reserve: 48 hours when fully wound

Photo of the movement Decalogue Rega watch


Case dimensions: Diameter 40 mm

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