(I am greatly indebted to the House of Longines website for much of the following information)

Prior to their acquisition by the Swatch Group in 1994, Longines was a Swiss brand of deep history, producing the watches of aviators Charles Lindbergh and Amelia Earhart, and being a primary provider of event timing for both the Olympic Games and decades of automobile racing. According to their official website, Longines produced their first chronograph in 1878, and their caliber 19CH served as timer to the first modern Olympics held in Athens in 1896. Their first wristwatch chronograph was the Caliber 13.33Z, circa 1910, and in 1936 Longines introduced the first wristwatch flyback chronograph, the extraordinary Caliber 13ZN.

About a decade later, in 1947, Longines followed up with what many regard as one of the finest and most beautiful wristwatch chronograph movements ever, the Caliber 30CH. Remarkably, it would prove to be the last such in-house movement ever from Longines, and although they continued to produce excellent chronographs for a few more decades, they were all based on the work of others.

Most 30CHs were unusually large for the era, and the present watch is no exception. It is 38mm diameter, exclusive of crown, and about 10mm thick. The hands and tachymetre scale are a seductive deep mid-afternoon blue, and the dial is softly brushed silver-gray; engraved subdials and very crisp black printing complete the design. I think that the details are proportioned near perfectly, and the whole is quite readable and serene.

The action of the chronograph pushers is seductive; smooth and soft, but with a very crisp feel and a slightly audible "zing!" when activated. The movement is 13 lignes (just under 30mm diameter), 6.2mm thick, and features 18 jewels, a screwed monometallic balance and Breguet hairspring. It runs at the traditional 18Kbph, and has a very interesting architecture. While the balance is topside-up, it is located way at the bottom of the movement. The pivoting wheel which engages the chronograph seconds is unusually located on the balance side, and the switching works are also inverted. Although not unique, these solutions are apparently not chosen very often.

Because all the levers and springs for the chronograph functions are exposed, the view into the movement is pretty complicated. Over the years this caliber sported various finishes, but I think the present "technical" style of straight-grained steel levers and springs, along with gently curved machine stripes for the bridges and plate is most suitable for this complicated movement. Execution is first-class; there must be several feet of edges here, and it is all very smooth, whether sharp or anglaged. The screws are polished and beveled all around, and the wheels are exceptionally neat.

This view shows column wheel (right) and the bridge carrying the chronograph wheels (left). The large levers near the center control the flyback (return) mechanism.

The same works from the other side, I think this picture captures a bit of the movement as three-dimensional sculpture, and highlights the beautiful finish!

This is the pivoting wheel which transfers power from the timekeeping train to the chronograph works. Even without Geneva stripes the bridges are truly artful:

All the springs are cut from sheet steel, and shaped to provide just the right amount of pressure at just the right angle and place. This is one of my favorites, the ultra-thin piece which damps vibration on the jumping chronograph-minutes wheel:

Classic profile, with large traditional crown:

All of this is easy to appreciate thanks to the absolutely perfect display back!

This is a relatively large watch, with robust features.

Inside the original back: