Grand Seiko Heritage SBGW309 / SBGW311 / SBGW313 – Mt. Iwate pattern

Quick specs Grand Seiko Heritage SBGW309 / SBGW311 / SBGW313 – Mt. Iwate pattern
Price: $ 5,900 | € 6.300 | £ 5,500 | CHF 6’300
Size: 36.5 mm
Reference:
SBGW309 (blue)
SBGW311 (green)
SBGW313 (pink)

The Grand Seiko Heritage SBGW309 / SBGW311 / SBGW313 – Mt. Iwate pattern models are part of the 44GS series. A reference to the case of the first Grand Seiko’s from the 1960s. Clean, solid dress watches that get some spice with so called Mount Iwate pattern dials.

It is Grand Seiko’s signature pattern, named after the ridged contours of this mountain, which is visible from the windows of the Grand Seiko Studio in Shizukuishi, Japan. This dial type here comes in blue for the SBGW309. This blue is inspired by wind-blown, ice-covered trees that transform into snow monsters, “juhyo” in Japanese.

Small-ish dress watch size

Then the SBGW311 comes in a kind of olive green, inspired by the rainy season in the early summer, called “tsuyu” in Japanese. And the pink SBGW313 is inspired by the viewing of cherry blossoms, “hanami” in Japanese. This one has a green central seconds hand, the other two models only have steel colored hands.

The size of the stainless steel case of these Heritage models is 36.5 millimeters. Now, even 34 millimeters (think 1950s dress watches) can look good on a regular wrist size, so 36.5 will do as well. But the “regular” dress watch size these days is 38 millimeters, so make sure it fits well before buying one.

The Grand Seiko Heritage SBGW309 / SBGW311 / SBGW313 – Mt. Iwate pattern has a power reserve of 72 hours

The Grand Seiko caliber 9S64 (est. 2011) is the engine of this Grand Seiko Heritage SBGW309 / SBGW311 / SBGW313 – Mt. Iwate pattern. A hand-wound mechanical movement with a power reserve of 72 hours. The precision parts are crafted with so called Micro-Electro-Mechanical Systems (MEMS) technology.

It’s an advanced semi-conductor manufacturing technology with which they can produce lightweight parts with extreme precision and to tolerances. The result is more accuracy (+10 to -1 seconds per day with normal daily use) and less friction. Among other things leading to more power reserve.

Mainspring from Spron510

More power reserve is also achieved by a thinner and longer mainspring. Seiko makes it from the alloy Spron510, a combination of mainly cobalt, nickel, chromium, and molybdenum. It is comparable with the Nivaflex mainsprings from the Swiss watchmaking industry.

These references SBGW309 / SBGW311 / SBGW313 come on a stainless steel bracelet with three-fold clasp with push button release. And unfortunately, often with Grand Seiko models, these ones are only available in the United States.