Hacking the 7S26 and other non-hacking movements

Like many automatic movements, Seiko's 7S26, found in most of their lower end automatics, is non-hacking. Hacking is the ability to stop the second hand so you can sync the time to another timepiece. This is usually done when you pull out the crown to set the time. Some watches have additional buttons to stop the movement for this purpose.

Disclaimer Jargon: What I am about to explain should not be taken as a how-to on all watches using this movement. I am not a horologist and cannot guarantee that this will have no ill effect on your movement. I will say that this is a common practice and I have heard of no problems in doing so.

1. Pull the crown to the second position (when you can move the hands) and set your time.
2. To stop or even reverse the second hand, slowly move the minute hand back a few minutes. When you stop do not release the backwards pressure on the crown. You should see the second hand stopped or moving slowly backwards at this time. If it is moving backwards ease up a bit on the crown until the hand stops. On some watches the crown may have enough resistance that you can let go and the second hand will remain still. Make sure it is not moving in reverse.
3. At this point the minute hand should be a few minutes early. By this I mean if the current time is 7:30, the minute hand should be on or around 7:28. Wait for the seconds on the other clock/watch to match your watch. As soon as this happens begin to advance the minute hand forward to the correct minute. This should resume the second hand and in effect set your watch to the correct minute.

Now you can set your day/date and voila, a perfectly set 7S26. This comes in handy when you are trying to check the accuracy on your clock or in military applications when you have to sync your time with the team.

I have found this technique to also work on other non-hacking automatics and manual movements including the Vostok 2416 B, Poljot 2614, Poljot 3133 and the Miyota. I also have a 1970s Tissot with unknown automatic inside that this also works with.