Why do watches use IIII instead of IV for the number 4?

This is known as the "Watchmaker's Four." We use IIII instead of IV primarily for visual symmetry. On a round dial, the four characters of IIII perfectly balance the four heavy characters of VIII (8) on the opposite side. It also creates a harmonious pattern: the first four numbers use only I, the next four use V, and the last four use X. This classical tradition is kept alive in our Swiss Made timepieces.