At midnight, the islands' time zone shifted west of the International Date Line, reversing 120 years of being east of the marker, Voice of America reported Friday.
Officials said the change corrects a calendar issue that had Samoa on Sunday while its trading partners were working on Monday. Similarly, when Samoa was conducting business on Friday, its trading partners were enjoying time off on Saturday.
One official said the shift made it easier for Samoa to do business with New Zealand, Australia, Japan and China.
The current time zone was agreed to in 1892 so the island nation could work with American traders based in California, Voice of America said. However, the country now does not do as much trading with the United States as it does with other countries.
The International Date Line is a north-south imaginary line that designates the place where each calendar day begins.
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