How to open the back - Bulova Watch

1

Determine the type of case back on the watch. Set the watch face down on a soft surface and look at the back. If it has slots, it is defined as a screw-back case. If it is smooth, it is defined as a snap-back case.
2

To open a screw-back watch, use the metal blade of a standard screwdriver to turn the slots counterclockwise. A case-back wrench, which can be purchased at watch-repair stores, can also be used. Set the metal tips of the wrench into the back's slots and turn it counterclockwise to open.
3

For a snap back case, place the metal blade of a standard screwdriver in the indent between the watch and the case. Gently apply pressure to lift the case up and off of the watch.
4

Close the case back by setting it back onto the watch. For snap-back cases, line up the indent on the side of the watch and press gently on the case back to close. For screw-back cases, use the screwdriver blade or case-back wrench to turn the slots clockwise, thereby closing the case shut.