Through most of the 20th century, watch casebacks were solid steel or gold, sealed against water and dust. The movement was an internal mechanism, visible only to the watchmaker during service. Cases were branded with engraved logos, model names, serial numbers, and water-resistance markings; the back was a functional structural element rather than a viewing window.
Exhibition casebacks emerged commercially in the 1980s as the mechanical-watch revival post-quartz-crisis emphasised the movement as artistic / engineering object. Early adopters: JLC Reverso (1986 reissue), Audemars Piguet Royal Oak (1990s revisions), and various small-volume haute-horlogerie pieces. By the late 1990s exhibition backs had become standard at the premium tier; by 2010 they were standard across mid-tier mechanical production.
"You bought the watch for the dial. You kept the watch for the back."- Watch enthusiast on the exhibition caseback experience
The construction: a sapphire crystal disc is bonded into a steel or gold caseback ring; the assembly screws or snap-fits into the case middle in the same way a solid caseback would. Water-resistance is maintained via gasket between the sapphire and the metal ring. The sapphire is significantly more expensive than the steel disc it replaces (sapphire of caseback diameter costs CHF 30-100 vs CHF 2-5 for steel), but the cost is small relative to the watch's retail price.
Functional trade-offs: the sapphire caseback is weaker than solid steel against impact and high pressure; sapphire shatters under sharp blows where steel would deform but hold. Dive watches with high water-resistance ratings (300m+) typically retain solid steel casebacks for structural margin; the Rolex Submariner, Sea-Dweller, and Deepsea all use solid steel. Tactical and military watches (Sinn EZM-series, Bell & Ross BR-X1) similarly retain solid backs for impact resistance.
For buyers, the exhibition caseback is part of the modern luxury-watch experience: the user can flip the watch over at any moment and see the rotor, balance wheel, and finishing details. The visual reward is significant on well-finished movements (anglage, côtes de Genève, hand-engraved balance cock); on less-finished movements (ETA 2824 base, simple Sellita) the exhibition back is more honest signalling than aesthetic gain. Tudor Black Bay 58 deliberately retains a solid back as a vintage-aesthetic choice; the modern Tudor Pelagos has an exhibition back. The choice carries brand-tier and aesthetic signals beyond pure visibility.
