Seiko 8C23-9040 Watch Guide The Seiko 8C23-9040 is a watch model based on the 8C23 movement.Other models with the same movement8C23-50008C23-500A8C23-50108C23-501A8C23-50208C23-50308C23-503A8C23-50408C23-504A8C23-50508C23-505A8C23-50708C23-50808C23-508A8C23-50908C23-509A8C23-51008C23-510A8C23-51108C23-511A8C23-60008C23-60108C23-60208C23-60308C23-60408C23-60508C23-60598C23-60608C23-60708C23-60808C23-60908C23-61008C23-70008C23-80008C23-8010