Shabbos: Self-wind watch

I just bought a self-wind watch I would like to know may I wear it on Shabbos?

Thank you for your question.

There are two types of mechanical watches: those that need to be manually wound and the more modern ones, known as automatic or self-winding watches, which are wound by the movement of one's hand. The main point is that through movement or manual winding, the 'mainspring' is wound, which then rotates to power the watch and display the time.

Regarding the halachic perspective on wearing such a watch on Shabbat, we need to analyze two points: 1. May one wind a manual watch on Shabbat? 2. May a person wear a self-winding watch on Shabbat?

Winding a watch on Shabbos .

The Shulchan Aruch, Orach Chayim, Siman 316,3, writes as follows:

שולחן ערוך אורח חיים הלכות שבת סימן שלח סעיף ג

זוג המקשקש לשעות, עשוי ע"י משקלות, מותר לערכו ולהכינו מבעוד יום כדי שילך ויקשקש כל השבת.

A clock that chimes every hour, operated by weights, is permitted to be set up and prepared while it is still day (before the beginning of shabbos) so that it may continue to chime throughout the Sabbos.

Explains the Mishnah Berurah (Seif Katan 14) that the reason it is permitted to wind it before Shabbos and let the clock run on Shabbos, is because we are not concerned that people might say that a person wound it on Shabbos.

The Mishnah Berurah goes on to say (seif Katan 15) that to wind it on Shabbos would be forbidden to do so and according to some halachic opinions it is considered a Torah prohibition of ‘Tikun Maneh’ of repairing a utensil.

The same halacha would be with the manual watch, it would be forbidden to wind up on Shabbos however if it was wound up before Shabbos then one can wear it on Shabbos.

However, when analyzing a self-wind watch since it is being wound throughout Shabbos it is forbidden to wear it on Shabbos.

There is also a type of watch called Eco-drive which gets charged with sunlight and even florescent light same too such a watch would be forbidden to wear on Shabbos.

So, we find that winding a watch by the movement of the hand is forbidden on Shabbos. One may ask, what about children's toys that need to be wound up for the car to move? Are they also prohibited? According to halacha, we are stringent that an adult should not wind up such a car. Nevertheless, if a child is playing with such a car, we don’t take it away from him as we do with other muktzah. The reason is that the car is not entirely like the case of the watch, without being wound up, a watch is worthless and provides no benefit, whereas a car even if it is not wound up is still a toy car, and a child can still use it to play. Therefore, it is not considered as a Tikun Maneh, like a watch. Also, since the energy from the spring is short-lived, as the car will only go for a few seconds, it is not considered a melacha. This is similar to when one opens a door attached to a spring: opening the door winds the spring, but since it lasts only a few seconds, it does not have the status of a melacha.

However, the reason we are stringent that adults shouldn’t use it is based on the Chazon Ish, Orach Chaim, Siman 50, Seif Katan 9. The reason it is prohibited to wind the spring of a mechanical watch is not that you are fixing a broken watch by winding it, but rather the reason is that you are creating energy, and creating energy is forbidden on Shabbos (either because of 'makeh be’patish' or 'boneh'). Therefore, according to the Chazon Ish, when it comes to winding up a toy car, the earlier explanation won't help since one is creating power to make the car go, and thus we are stringent not to use such a car on Shabbos. However, if a child is playing with it, we don’t take it away from him since there is room for leniency as explained earlier.

Wishing you well.

Shulchan Aruch, Orach Chayim, Siman 316,3,

Mishnah Berurah ibid

Chazon Ish, Orach Chaim, Siman 50, Seif Katan 9