Citizen houses the instructions for the GN-4W-S movement under their "Promaster" or "Nighthawk" technical guides.
The GN4-W S12G is a solar-powered Eco-Drive model that uses light to charge an internal rechargeable cell, removing the need for regular battery swaps. It typically includes standard analog timekeeping, date display, water resistance, and a durable stainless-steel case and bracelet.
The best part of an Eco-Drive is that it has no battery. However, it does have a rechargeable cell. Your manual will describe the Low Charge Warning:
Refer to your manual link for the exact diagram, but the general process is:
Your watch has two pushers: Top (Start/Stop) and Bottom (Reset).
| Action | Button Sequence | Result | |--------|----------------|--------| | Start timing | Press top pusher (A) | Large seconds hand begins moving | | Stop timing | Press top pusher (A) again | Chronograph stops, displays elapsed time | | Reset to zero | Press bottom pusher (B) | All chronograph hands return to 12:00 | | Split timing (if supported) | Press bottom pusher while running | Temporarily stops display while internal timing continues |
Important from the manual: Do not press the reset button (bottom) while the chronograph is running unless you fully intend to zero out the measurement. This can confuse the hand alignment.
Unlike quartz watches that require battery changes every two years, your Eco-Drive needs only light and basic care.