Hamilton Jazzmaster Open Heart Auto H32675140

The storyWhy this reference matters

Open heart sounds like haute horlogerie and is not, which is exactly the good news. A true skeleton means hollowing out bridges and plates, which pushes up the price of the movement and usually costs it some robustness. Hamilton does the opposite here: it leaves the H-10 calibre intact and cuts the dial away above it, with the edges of the opening bevelled and polished. The result shows balance, barrel and part of the gear train without a single component of the engine having been touched.

The H-10 is the brand's workhorse: automatic, twenty-five jewels, three hertz and eighty hours of reserve, with a titanium-based Nivachron hairspring to shrug off magnetic fields. It beats slowly on purpose. Those 21,600 vibrations per hour are what let it stretch the barrel out to a good three days, and on this model they earn a bonus. A balance running at 3 Hz is far better to watch through a hole in the dial than one at 4.

The case measures 40 mm, with horned lugs and an art deco air, and barely 11 mm tall; the back is glass, so the same movement can be looked at from both sides. Watch Clicker calls it the spiritual successor to the Omega De Ville Hour Vision for a good deal less money, a comparison that says something flattering about the Hamilton and something uncomfortable about how much other display cabinets charge for a finish that comes as standard here.

SpecificationsThe numbers, in one table

IdentificationHow to tell it apart

This reference is the smoked blue dial on the steel bracelet, H32675140. Within the same family there are variants that get mixed up easily, because the H32675540 is also blue and the H32675170 is burgundy. Look at the dial and bracelet together rather than at the colour alone. The original bracelet's part number is H6054251001, useful if you ever have to replace the whole thing.

Pocketable measurements: 40 mm across, 11.05 mm thick, 50 mm lug to lug and 20 mm lugs. Water resistance is 5 bar, which is 50 metres, and that puts it in dress watch territory with a margin for rain rather than in the water. Sapphire crystal with anti-reflective coating, and an open back, also sapphire, screwed to the case.

The cut-out in the dial is not just any round hole. It is an irregular shape with bevelled edges, and through it you see the balance, the barrel and some of the gearing. If in a sales photograph the opening looks like a plain circle with a balance sitting inside it, either it is not this model or it is another brand pulling the same trick with a good deal less craft.

CollectingWhat collectors check

The predictable weak spot is the bracelet. At this level, folding clasps pick up play over the years and the links loosen at the pins. Open and close the clasp several times looking for sideways movement, and shake the bracelet gently near your ear: if it rattles, the wear is spread through the whole thing. Replacing it entirely is possible, but it pushes up the cost of what is supposed to be a sensible purchase.

The second check is the dial. Because it is cut away and bevelled, any knock to the crystal or a badly done opening leaves marks right at the edge of the hole, which is exactly where the eye goes. Look at that outline in raking light. And make use of the glass back: the perlage on the movement should look clean and even, and screws with chewed slots give away careless hands inside the case.

On value, be honest with yourself. This is not a rare or a limited watch, so scarcity will not work in your favour. What moves the resale price here is prosaic: a complete bracelet with all its links, box and stamped warranty, and a dial with no marks around the cut-out. Buy it because you like looking at it, not because you expect it to do anything with time.

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