Citizen Tsuki-yomi A-T Moon Phase Titanium Purple Dial Eco-Drive 100M Watch

Titanium Moon-Phase Solar Watch

The Citizen Tsuki-yomi A-T BY1010-81Z is a men’s titanium wristwatch with a purple dial and moon-phase complication. Solar Eco-Drive movement charges from any light source, removing the need for battery changes. A 43.00 mm case and 10.90 mm profile sit on a matching titanium bracelet with a deployment clasp. Water resistance is rated to 100 metres.

Installation And Common Issues

Adjust the bracelet by removing or adding links with standard watch tools; the deployment clasp then secures with a single press. Pull the crown to the first position for date correction and to the second for time and moon-phase setting; the atomic timekeeping signal synchronises automatically overnight. Avoid operating the crown or pushers while the watch is wet, and rinse with fresh water after salt-water exposure to keep the gaskets clean.

Pre-Purchase Checks

Verify that a 43.00 mm case diameter and 10.90 mm thickness suit your wrist size and shirt-cuff clearance. Confirm that 100-metre water resistance meets your swimming or snorkelling requirements. Ensure you can provide regular light exposure — natural or artificial — to keep the solar cell charged. The fixed bezel and sapphire crystal are not user-replaceable, so factor long-term durability into the decision.