The Decalogue Rega is the flagship and most sophisticated model in the Decalogue collection. It is the only wristwatch in the world that measures time in the traditional Jewish way, including small units such as heleks (1/18 minute) and regaim (singular: rega) (1/76 helek or about 0.044 seconds). Heleks and regaim have been used by Jewish astronomers since ancient times and, together with the days and hours, form the basis for measuring time in the Jewish lunar calendar. The rega hand is one of the fastest in watch mechanics, making one revolution every 7.2 seconds. Konstantin Chaykin mounted this hand on the back of the movement, which is driven by a special gear. The back of the movement is also decorated with an applied miniature figure of a heraldic lion, a symbol of the city of Jerusalem. There is something special about observing the watch being built. It is not just a mechanical process, but a true art in which the meticulous work of the master craftsman is combined with the precision of technical thinking. Assembling a watch is something that can fascinate, inspire and convey a sense of wonder. The caseback with the sapphire window of the Decalogue Rega watch reveals the traditional hand-wound movement with an unusual design, including the applied miniature figure of a heraldic lion and the rapidly rotating hand that indicates the time in rega, the smallest unit of time measurement in the tradition of Jewish timekeeping. The caliber K.01-1 PS of the Decalogue Rega watch was developed by Konstantin Chaykin to indicate the time in helek and rega, the small units of time measurement in the tradition of Jewish timekeeping. The rapidly rotating hand, which indicates the time in rega, is located on the back of the movement. The movement is made entirely in Konstantin Chaykin Manufacture according to the standards of haute horlogerie, using traditional techniques for finishing the components: Côtes de Genève, perlage, fine straight and circular grinding, hand-polished chamfers, engravings, polished screw, pin and jewel recesses, ball polishing of the pivots and rhodium plating. The special features of the movement are the miniature golden figure of a heraldic lion, the symbol of Jerusalem, on the movement back and a ‘Pac-Man’ regulator, developed by Konstantin Chaykin for fine adjustment of the hairspring. Caliber: K.01-1 PS, hand-wound, made by Konstantin Chaykin Manufacture Power reserve: 48 hours Functions: – Hour and minute hands rotating counterclockwise; – Moonphase display; – Helek hand; – Rega hand.