iwc IW3921 Operating Instructions Manual page 25

Setting when crossing the Inter­
nation al Date Line:
– When crossing the International Date
Line in a westerly direction (you enter
the next day, regardless of the time
of day), simply turn the time forward
to the new local time, and the date
change will take place automatically.
– When crossing the International Date
Line in an easterly dir ection (you
enter the previous day, regardless of
the time of day), you must likewise
set your watch forward to the new
local time. However, your watch will
now indicate the wrong date (one
day too many). This incorrect date
indication can be corrected by reset­
ting the hands twice, by 12 hours on
each occasion:
D A V I N C I P E R P E T U A L C A L E N D A R C H R O N O G R A P H
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