Sinn 936 S: bicompax chronograph returns to tool watch clarity

Sinn has returned the bicompax chronograph to its catalogue with the 936 S, a two-register design that strips away the three-subdial complexity favoured across luxury watchmaking for the past two decades. The choice reflects the brand’s philosophy: timing instruments should prioritise legibility and functional purpose over decorative elaboration. A sixty minute scale on the chronograph counter marks a deliberate return to classical proportions.

The dial presents itself in matte black with pale green luminous indices that catch light with restraint rather than flash. A red enamel accent on the chronograph seconds hand guides the eye without distraction. Two subdials occupy the field: running seconds at three o’clock and the minutes register at nine, its sixty division scale reducing visual noise while preserving the information a timing tool requires. The SZ05 automatic calibre powers the mechanism with the robustness Sinn applies to every component it assembles.

What distinguishes the case is Tegiment, Sinn’s proprietary hardening technology developed and refined over decades in Frankfurt am Main. This process renders the steel significantly harder than conventional tool watch cases, protecting against the scratches and abrasions that accumulate through professional use. The proportions follow function: pronounced bezel for grip, functional lugs, surfaces finished to withstand rather to impress. Water resistance and shock absorption emerge from the same engineering philosophy that shaped the dial.

Sinn’s chronograph lineage extends back through generations of precision work for pilots, divers and engineers. The bicompax format, once standard, became rarer as three and four register chronographs dominated the luxury segment. By returning to two subdials, the brand makes a deliberate argument: simplicity in function and clarity in reading constitute their own sophistication, without concession to trend. Each watch undergoes quality control protocols in the brand’s manufactory that exceed standards applied to many houses’ top collections.

The 936 S is available through authorised Sinn retailers and at sinn.de.

Sinn’s Frankfurt manufactory has applied Tegiment hardening to steel cases since the 1990s, a process that increases surface hardness to approximately 1,200 Vickers, comparable to tool steel used in industrial applications. The treatment emerged from the brand’s work supplying precision chronographs to German pilots and technical professionals, where durability under sustained use determined survival in the catalogue. Modern Tegiment variants, refined over three decades, now form the foundation of every Sinn sports watch, distinguishing them from conventionally hardened competitors in ways that become visible only after years of wear.

The SZ05 automatic calibre, visible through the 936 S case back, operates at 28,800 vibrations per hour and carries a power reserve of forty two hours. Sinn manufactures the movement in house, controlling every component from escapement to balance wheel, a decision uncommon among independent watch brands and one that reflects the company’s insistence on mechanical reliability over outsourced assembly. The chronograph mechanism engages without backlash, a refinement that requires hand finishing of the cam ring and lever.

The 936 S dial measures 41.5 millimetres in diameter and sits 12.4 millimetres thick, proportions that favour wrist presence without the visual weight of oversized sports watches that became fashionable after 2010. The case back carries a sapphire crystal, unusual in tool watches, allowing owners to observe the SZ05 and verify the mechanism’s condition without requiring a watchmaker’s intervention. Water resistance reaches 300 metres, sufficient for professional diving and substantially beyond the requirements of the chronograph’s primary users.

The watch carries a two year international warranty and returns to Frankfurt for servicing, where technicians assess wear and re apply Tegiment if necessary after disassembly. Sinn offers spare parts for calibres dating back to the 1970s, a commitment to longevity that shifts ownership from consumable purchase to instrument acquisition. The 936 S arrives on a structured metal bracelet or fabric strap, both engineered to the same standards as the case, and costs €4,880 as of January 2025.

Imagery courtesy of Sinn Spezialuhren (@sinn_spezialuhren).