Automatic Spring Drive 3-Day Chronograph GMT
Spring Drive Calibre 9R86 may well be the world's most accurate spring-driven chronograph. It delivers a precision of ±15 seconds a month, or ±1 second a day and, equally importantly, measures elapsed time not to the nearest fraction of a second but exactly, thanks to the fact that the glide motion hands stop at the very instant that the button is pressed.
The 72 hour power reserve is maintained even if the chronograph is in operation.
|Winding mechanism||Automatic with manual winding|
|Accuracy||±1 second per day (±15 seconds per month)|
|Power reserve||Approximately 72 hours|
|Number of jewels||50 jewels|
|Features||-Power reserve indicator
-Dual time function with 24-hour hand
-Quick correction function of time difference adjusting to a calendar
Achieving a level of stopwatch accuracy equivalent to the accuracy of the Spring Drive calibre itself would not have meant much if this accuracy were lost in the operation of the stopwatch. To minimize time measurement errors when the chronograph buttons are pressed, the operation of the buttons was made as precise as humanly possible. A two-step READY/START mode was adopted to ensure that the stopwatch operation would be error-free. It is the same mechanism as is used in Seiko’s hand held stopwatches for professional sports use. The chronograph enters READY mode when the push button is lightly pressed. A further press then starts the stopwatch.
What makes 9R Spring Drive special?
Spring Drive, one of the great innovations in modern watch making history, regulates a spring-driven movement with state-of-the-art electronic technology that functions without batteries or other external power source. Its sole power source is a mainspring, which drives a series of gears. A rotor, connected to the end of these gears, generates a small electrical charge that activates an electronic circuit and quartz oscillator. Its accuracy is unprecedented for a watch wound by a mainspring. The development of the 9R Spring Drive movement was possible only because Grand Seiko is one of the few manufacturers with expertise in both mechanical and electronic watches.
Calibre 9R86 Models
9R Spring Drive Movement
The three movements at the heart of Grand Seiko
One of the world's foremost mechanical movements, the culmination of high-precision micro-engineering and the attention to detail of Grand Seiko's expert watchmakers.
Spring Drive is a unique movement that delivers one-second-a-day precision, using just the power of a mainspring.