In the meantime, there’s some evidence that international distributors hated the inconsistent and infrequently illogical numbering methods of their Swiss overlords. Inside of, you’ll find the trademarked Citizen eco-drive movement. It powers your watch with light, therefore you don’t require a battery to tell the time. It’s sustainable and trusted. https://www.watchesworld.com/a-history-of-watch-reference-numbers/