Got this beauty [SixOneThreeEight]-ZeroZeroFourNine in almost NOS condition with original Z040S fishbone bracelet. Intrigued by the crown and pushers at the 12 o' clock. And I have a soft spot for watches with the day-date at 6! Still one of my faves to date. Production date: Oct, 1977[SixOneThreeEight] is the first integrated chronograph movement renowned for its ruggedness, complete with column wheel for switching between functions, vertical clutch for a very slick and fluid chrono's engagement and balance bridge. The only other watch with this combination is the current Rolex Daytona.
Cal [SixOneThreeEight] was introduced by Seiko in 1970 and used in the 1970s Seiko 自动 chronographs. [SixOneThreeEight] has 21 jewels and dimensions of [SixOneThreeEight] are 27.4 x 7.9 mm, beating at 21,600 bph. Watches with [SixOneThreeEight] movement have two subdials (a 12-hour counter, and another 30-minute counter). In terms of accuracy, Seiko promised that both [SixOneThreeEight] and [SixOneThreeNine] movements will keep time within +35 to -20 sec per day.
