The document explains how to open different Seiko watch cases, noting that some are monocoque and require access from the front. It provides detailed steps for safely removing the case, crystal, and gasket for various models, including divers and chronographs. Caution is emphasized to avoid damaging the watch during the process.

2. Not all Seiko cases have a removable back.
These are monocoque (one-piece) cases that you access from the front.

3. Recommended: A proper case opener.
A cheap penknife is more likely to damage you or the watch.

4. Find the notch.
If there’s a gap between the bezel and case, push in the opener (don’t twist).

5. Lift off the crystal.
Loosen by pushing the opener in at several places around the bezel.

6. Lift off the gasket.
Be very careful not to scratch the dial.

7. Release the stem.
Look for a small lever between the dial and case.

8. And you’re done!
Re-assembly is the reverse of these steps.

9. Use a crystal press to fit the bezel.
Put a plastic sheet over the watch first to protect it.

10. Now on to a diver.
There’s no notch – just push the opener between the bezel and case.

11. Remove the bezel by pushing in.
Do not twist the case opener – it’ll damage the case.

12. Undo the crystal retaining ring.
Use a Jaxa-style opener, turning it anti-clockwise slowly and carefully.

13. Prepare a suction cup
The crystal is pushed in so attach a suction cup, e.g. from a hardware store.

14. Lift off the crystal.
The dial is now exposed so move the crystal far away.

15. Release the stem.
Push down on the lever between the dial and case.

16. That’s it for the diver!
Now let’s move on to a chronograph…

17. Find the tabs.
There should be one or two on opposite sides of the case.

18. Press in firmly.
Press in the tabs on both sides before pulling off the case.

19. Lift off the crystal.
Lift without twisting to avoid damaging the dial.

20. Remove the gasket.
Carefully loosen it all around before lifting it off.

21. And that’s it!
Release the stem with the lever as before.