Hamilton Jazzmaster Open Heart Auto 42mm
About This Watch
The Hamilton Jazzmaster Open Heart Auto is one of the most iconic watches in Hamilton's catalog and arguably the watch most responsible for the brand's popularity among younger watch enthusiasts discovering mechanical horology for the first time. The signature open heart aperture on the dial reveals the balance wheel and escapement — the beating heart of the mechanical movement — creating a hypnotic window into the precision engineering that makes mechanical watches tick, quite literally. The blue dial variant is the most popular colorway, offering a rich sunburst blue ground that contrasts beautifully with the silver-toned movement components visible through the cutout. The asymmetric placement of the open heart aperture between 10 and 2 o'clock, balanced by the date window at 6, creates a dial layout that is distinctly Hamilton and immediately recognizable. The H-10 caliber visible through the aperture features decorated components including the rhodium-plated balance bridge and blued hairspring, providing genuine visual appeal beyond the mechanical fascination. At 42mm, the Open Heart is sized to show off its signature complication with maximum impact, though the 50.5mm lug-to-lug keeps it manageable. The brown leather strap adds warmth to the blue dial, creating a classic combination. The Jazzmaster Open Heart has become a cultural touchstone in the watch community — it is the watch recommended to friends asking "what's a good first mechanical watch?" more than perhaps any other, and it earns that recommendation through genuine visual drama and solid mechanical substance at an accessible price.
In-Depth Review
# Hamilton Jazzmaster Open Heart Auto 42mm Editorial
Swiss watchmaking needn't command five-figure pricing to deliver genuine substance, and Hamilton's Jazzmaster Open Heart Auto demonstrates this principle effectively. The 42mm stainless steel case houses the brand's H-10 automatic caliber, a workhorse movement displaying 80 hours of power reserve and visible through the open heart dial—a design choice that telegraphs mechanical authenticity without pretension. The blue dial paired with a brown calf leather strap strikes a genuinely appealing aesthetic, executed with the restraint expected from a marque with deep roots in American industrial design heritage. At just 11.7mm thick, the watch maintains reasonable wrist presence without the bulk that plagues many contemporary dress watches, while 50 meters of water resistance provides practical reassurance for daily wear.
This watch targets discerning buyers seeking legitimate mechanical horology at accessible prices—professionals who want visible craftsmanship without luxury brand markup, and collectors building foundational collections around brands with genuine manufacturing heritage rather than logo equity. The Jazzmaster line itself draws from Hamilton's 1958 original, lending historical credibility often absent in cheaper mechanicals.
In the current market landscape, the Open Heart competes directly with offerings like the Tissot PRX Automatic and Citizen Promaster, though it distinguishes itself through Swiss provenance and a more classical aesthetic. At street prices around $795, it represents competent value in the entry-level automatic segment, though buyers prioritizing contemporary styling or integrated bracelets may find alternatives more compelling.
Specifications
Movement
| Movement Type | Automatic |
|---|---|
| Caliber | H-10 |
| Power Reserve | 80 hours |
| Frequency | 21,600 vph |
| Jewels | 25 |
Case
| Case Diameter | 42.0mm |
|---|---|
| Case Thickness | 11.7mm |
| Case Material | Stainless Steel |
| Crystal | Sapphire |
| Bezel | Fixed, polished |
| Dial Color | Blue |
| Lug Width | 22mm |
| Lug-to-Lug | 50.5mm |
Features
| Water Resistance | 50m / 164ft |
|---|---|
| Bracelet/Strap | Brown calf leather strap |
| Clasp | Pin buckle |
| Weight | 78g |
| Complications |