Casio 3427 Operation Manual page 6

Operation Guide 3427
* As of June 2013, the offi cial UTC offset for Moscow, Russia (MOW) has been
changed from +3 to +4, but this watch still uses an offset of +3 (the old offset)
for MOW. Because of this, you should leave the summer time setting turned on
(which advances the time by one hour) for the MOW time.
This table shows the city codes of this watch.
The rules governing global times (UTC offset and GMT differential) and summer
time are determined by each individual country.
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