The Black dial version of Olympic One Stop Chronograph (also known as Seiko Crown Chronograph, also Seiko Mono Pusher) with excellent manual wind caliber 5719A.
Overall condition shows it has very long time 'mileage', the engraved torch and words on caseback almost gone. Serial number means it made in May 1964.
Bracelet is original also the clasp is correct.
Movement in action!