There was once a kind of jade bracelet called "taifei", which was not traditionally round but oblate. This had one benefit when worn on the wrist: it wouldn't rotate or move around easily. However, it's unclear how this taifei bracelet became associated with the term "mistress". Wearing a watch presents a similar issue; the watch can not only move up and down on the wrist but also twist sideways, causing it to shift out of position. Due to the weight of the watch, it usually shifts towards the outer lower side of the wrist, affecting readability and causing discomfort as well as being unattractive.
Both metal and leather straps have this problem, and the cause is mainly related to the tightness of the strap and the size and weight of the watch. Generally speaking, heavier watches with looser straps are more prone to this issue, but there are other reasons as well. Here's an analysis:
1. The lengths of the upper and lower parts of the strap are uneven. You can check this by holding the watch horizontally from the side with the clasp closed or connected. If it's a "butterfly clasp," the clasp part will not be parallel to the watch itself. When initially shortening the metal strap upon purchase, this should be considered. Sometimes, both sides need to be symmetrically shortened to make the clasp parallel to the watch.
2. From an anatomical perspective, the inner wrist bone should have at least two parts, including the radial carpal tunnel, ulnar carpal tunnel, and carpal tunnel. Therefore, most wrists are oblate. However, for those with larger wrists, thin wrists, or fleshy wrists, they may appear nearly circular. In such cases, the control over the watch might be poorer.
3. The structure of the watch and strap matters. For instance, bracelet-style straps that integrate with the case, when fastened, form a complete circle. These tend to have less support and are more likely to swing.
4. Conversely, if the metal strap is too loose or the leather strap is too thin and soft, it will provide insufficient support and be more prone to swinging. High-quality leather straps often have a gradual taper in thickness from the head to the tail, such as a men's strap that starts at 3.5mm thick and tapers to 2.0mm over about 60-70mm. This ensures good control, especially for larger and heavier watches.
5. A standard leather strap typically has lengths of approximately 70/110mm. Simple pin-loop structures provide less grip on the wrist compared to butterfly clasps, which are much better. The metal crossbar of a butterfly clasp is about 40mm long, forming a front-to-back clamp with the back cover of the watch, reducing twisting.
6. The material and shape of the strap matter. Smooth materials like tungsten steel and ceramic are more likely to roll, while narrow straps are more prone to movement. Broad and sturdy rubber straps adhere better to the skin.
To avoid lateral movement or drooping of the watch, I suggest appropriately tightening the strap. If it's a leather strap, consider replacing it with a slightly thicker and firmer one or switching to a butterfly clasp. For metal straps, check if the lengths of the upper and lower sections are consistent. Sometimes, shortening the strap section at the 6 o'clock side of the dial can help create a slight imbalance. Another simple method I often use is to invert the watch, placing the crown upward. You could also try swapping the upper and lower straps (though this might feel awkward when closing or removing the watch). Ensuring these adjustments can help correct positioning issues.