iwc PORTUGIESER PERPETUAL CALENDAR TOURBILLON Operating Instructions Manual page 8

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rotor made of 18­carat red gold winds
the watch in both directions of rotation
via the Pellaton winding system. Your
watch is equipped with a flying minute
tourbillon, a unique micro mechanism,
which minimizes the effect of gravity
on the accuracy. The tourbillon, an
invention made in the aftermath of the
French Revolution, has always been
regarded as the ultimate challenge
in the quest for absolute mechanical
watchmaking precision. More specific­
ally, the purpose of the mechanism is
to counterbalance the one­sided pull
of the earth's gravity on the balance.
This is because the residual gravita­
tional error of the balance influences
the accuracy, depending on the pos­
ition of the watch. Fortunately, there
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