If the time-only watch is a perfect solo, a "complication"—any function beyond displaying hours, minutes, and seconds—is a full orchestral score. Each complication adds a layer of mechanical intellect, solving a problem of physics with breathtaking ingenuity.
Imagine a mechanism that understands the vagaries of the Gregorian calendar, knowing the length of every month, even factoring in leap years, until the year 2100. The perpetual calendar is one of horology's most revered complications, a micromechanical brain that requires no adjustment for date until a century has passed. To own one is to wear a piece of historical and astronomical intelligence.
