Seiko Women's SXD646 Dress Two-Tone Watch

Seiko Women's SXD646 Dress Two-Tone Watch

My personal  Seiko Women's SXD646 Watch Review

Positive:

* Easy to read.

* Elegant, but not gaudy.

* Reliable watch

Negative:

* Big for for my small wrist

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The first Seiko Chrono

In 1969, Seiko introduced its first automatic chronograph. It was and is also one of the first automatic chronographs of history, a fact that is unfortunately ignored by most storytellers. Although is not the first to be presented, the Seiko Automatic Chronograph caliber 6139 automatic chronograph was the first to be in stores, available to the public.

 It is a chronograph with column wheel, based on the 6106 gauge. The 6139 has 30 minutes accumulator, double calendar 21,600 vph and versions with 17 and 21 rubies.

 Just one year later, Seiko introduced the caliber 6138. Is virtually the same 6139 with the same characteristics but with the addition of an 12 hours accumulator.

 The most interesting part of the new chronograph was hidden from the view of the user: the vertical clutch system. This is a system invented by Swiss manufacturing Pierce in 1938  This system was modified and improved by Citizen in 1965. Although already owned a Seiko chronograph since 1964, she only used this system for the first time in 6139 caliber. The clutch function is to activate and deactivate the chronograph function, coupling and uncoupling the central axis of seconds the rest of the main carriageway.