How can a simple date be displayed on a mechanical watch?

Displaying a simple date on a mechanical watch can be accomplished through various methods, and each of the listed options is a valid approach.

Using a hand involves having a dedicated indicator that points to the current date on a calibrated scale, often positioned around the watch dial. This can be an aesthetic and straightforward way to represent the date, allowing for easy reading at a glance.

An aperture with a magnifying glass, commonly known as a cyclops lens, enhances visibility by magnifying the date shown in a small window on the dial. This method is frequently used in watches to provide a clear view of the date without requiring additional space on the dial.

A retrograde hand, instead of moving in a continuous circular motion like traditional hands, sweeps over a scale and then jumps back to the start, creating a dynamic and unique date display. This adds a creative flair to the watch and can make the date display more engaging.

Since each of these methods is valid and serves a distinct aesthetic and functional purpose in displaying the date, the comprehensive answer acknowledges that all the approaches listed can coexist in mechanical watch design.