Seiko 6L35 Manuel D'instructions page 19

ACCURACY OF MECHANICAL WATCHES
The accuracy of mechanical watches is indicated by the daily rates of one week
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or so.
The accuracy of mechanical watches may not fall within the specified range of
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time accuracy because of loss/gain changes due to the conditions of use, such as
the length of time during which the watch is worn on the wrist, arm movement,
whether the mainspring is wound up fully or not, etc.
The key components in mechanical watches are made of metals which expand
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or contract depending on temperatures due to metal properties. This exerts an
effect on the accuracy of the watches. Mechanical watches tend to lose time at
high temperatures while they tend to gain time at low temperatures.
In order to improve accuracy, it is important to regularly supply energy to the
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balance that controls the speed of the gears. The driving force of the mainspring
that powers mechanical watches varies between when it is fully wound and im-
mediately before it is unwound. As the mainspring unwinds, the force weakens.
Relatively steady accuracy can be obtained by wearing the watch on the wrist fre-
quently for the self-winding type and winding up the mainspring fully everyday
at a fixed time to move it regularly for the wind-up mechanical type.
When affected by external strong magnetism, a mechanical watch may loss/gain
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time temporarily. The parts of the watch may become magnetized depending on
the extent of the effect. In such a case, consult the retailer from whom the watch
was purchased since the watch requires repair, including demagnetizing.
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