A watch movement is the internal mechanism of a pocket watch or wristwatch, comprising the mainspring, gear train, escapement and balance that together measure and display the passage of time. The movement is the engine of the watch, and its quality, design and condition largely determine the value of an antique timepiece.
Early watch movements used the verge escapement and often a fusee and chain to even out the pull of the mainspring, and English examples frequently feature finely pierced and engraved balance cocks. Over the eighteenth and nineteenth centuries more accurate escapements were introduced, including the cylinder, duplex and detached lever, the last becoming the standard for quality watches. Swiss makers led the move towards thinner, factory-made movements, while English makers in centres such as Clerkenwell, Coventry and Prescot continued traditional methods for longer. Jewelled bearings reduced friction and wear. When assessing a movement, collectors look for the maker's signature, serial number, original parts, freedom from rust and a clean, unmolested appearance. Complications such as repeating work, chronographs and calendars add interest, and servicing should always be entrusted to a specialist watch restorer.
