The **calendar adjustment** in German watches operates on a fascinating mechanical principle

The **calendar adjustment** in German watches operates on a fascinating mechanical principle. Power is transferred from the **hour wheel**, which, through the gearing of the **calendar transfer wheel**, allows the **calendar dialing wheel** to rotate once every 24 hours. A **notch pin (or a spring-like mechanism)** on the calendar dialing wheel is tasked with moving the teeth on the **calendar disc**, which features 31 teeth and numbers.

The **calendar positioning rod**, under the tension of the **calendar positioning spring**, engages the teeth of the calendar disc, ensuring its accurate positioning. If the calendar mechanism employs a **slow crawl or quick jump** system, the transition between dates occurs gradually (starting from 8 PM to midnight); for an **instant jump** system, there’s an additional cam beneath the calendar dialing wheel, along with a **large lever and spring**. This setup compresses and then rapidly releases under the cam’s action, causing the calendar disc to swiftly move one tooth (or date) in an instant.

This intricate blend of gears, levers, and springs not only showcases the **ingenuity** behind German watchmaking but also ensures that the wearer always has the correct date displayed on their wristwatch, blending **functionality** with **mechanical beauty**.