1. The lengths of the high and low segments of the watch strap are different. This can be seen by holding the watch horizontally from the side. To close or buckle the strap, especially for a "butterfly buckle," the buckle area will not be parallel with the watch itself; when shortening the metal bracelet initially, this issue should be considered. Many things that appear simple require more humanized consideration. Sometimes, it is necessary to symmetrically remove links from both sides, with the principle being to align the buckle parallel to the watch.
2. From a human anatomy perspective, the wrist typically has at least two bones, including the radial and ulnar carpal tunnels and the carpal tunnel, making the wrist generally flat and round in shape. However, some people have larger wrists ("big wrists"), thinner wrists ("firewood wrists"), or wrists with more flesh, which may appear nearly circular. For these shapes, the control over the watch during wear might be less effective.
3. Related to the structure of the watch and its strap, such as those with an integrated case and bracelet design resembling a bracelet, when buckled, they form a circle with good support but may easily wobble if not worn snugly.
4. Conversely, if the metal bracelet is too loose or the leather strap is overly thin and soft, it will offer poor support to the watch, causing it to wobble. High-quality leather straps often have a gradual thickness change from the head to the tail, forming a sloping surface. For example, a men's leather strap might start at 3.5 mm thick at the head and taper down to 2.0 mm at the tail over a length of about 60-70 mm. These areas also contain added materials internally. Only such straps can provide good control over the watch, especially larger and heavier watches.
5. A standard leather strap typically has two segments measuring approximately 70/110 mm in length. If only a simple pin-and-loop closure is used, the clamping effect on the wrist is minimal. Using a "butterfly buckle" structure improves this significantly. The metal crossbar of a "butterfly buckle" is around 40 mm long and applies pressure from both the front and back of the wrist, preventing the watch from twisting.
6. The material and shape of the strap also play a role. Straps made from materials like tungsten steel and ceramics, which have smooth surfaces, tend to roll easily. Narrower straps are also more prone to movement, whereas broad and sturdy rubber straps adhere better to the skin.
To avoid lateral shifting or downward slipping while wearing the watch, I recommend appropriately tightening the strap. If using a leather strap, consider replacing it with one that is slightly thicker and firmer, or switch to a "butterfly buckle." For metal bracelets, check whether the lengths of the upper and lower segments are consistent. Sometimes, it is necessary to specifically shorten the strap segment near the 6 o'clock position of the dial to create a slight difference in length. Another simpler method, which I often use personally, is to invert the watch so that the crown faces upward when worn. You can also try swapping the top and bottom straps (though this might feel awkward when closing or removing the watch), ensuring that any adjustments effectively correct the issue.