http://gearpatrol.com/2015/02/13/complications-the-chronograph/Any function on a watch beyond merely telling time is called a “complication”, and it’s a fitting term. Even adding a date function involves the precise addition of gears and linkages to make that number flip over every 24 hours. Aside from the mechanical wizardry of watch complications, there is also a rich history intertwined with their development. Over the next several months, our “It’s Complicated” series will examine seven of the best known watch complications — the chronograph, the moonphase, the annual calendar, the minute repeater, the GMT, the world timer and the perpetual calendar — explaining how they work, their history and a handful of modern timepieces that best exemplify them. – Jason Heaton