Heart Beat

Look through the aperture and check that a balance is actually oscillating

A genuine Heart Beat shows a balance wheel swinging back and forth at the movement's beat rate, with the hairspring visible around it. What counterfeits and low-grade homages put behind the opening instead is a decorative wheel turning steadily, a printed disc, or nothing at all. An oscillating balance reverses direction constantly and unmistakably; a rotating decoration does not. This can be judged from a short video and does not require the watch in hand.

The aperture constrains how the movement can be oriented

For the balance to appear under the opening, the movement has to be positioned so that it does — which is a genuine design constraint rather than a decorative choice, and one a generic substituted movement will not satisfy. A Heart Beat dial over a movement whose balance sits elsewhere shows an empty or wrongly filled aperture, which is why the shortcut is a printed disc.