Caliber JJ01

Christopher Ward's jumping-hour module, which the house calls its first in-house module, mounted on a Sellita SW200-1. It credits the design to its former master watchmaker Johannes Jahnke. A jumping hour shows the hour as a numeral in a window that changes in a single step, and the usual fault is that the change lands a little before or after the minute hand reaches twelve, because the energy for it is built up in the last minutes of the hour. JJ01 draws that energy evenly across the whole hour instead, so the disc turns over as the hour arrives. The page gives 26 jewels and 4 Hz, and states the reserve as 38 to 41 hours.