The Nikkei average ended trading down 1.83 percent at 10,310.04 , a four-week low .
The Nikkei average .N225 was down 1.83 percent or 192.25 points at 10,310.04 , its lowest close since August 28 .
The Organization of Petroleum Exporting Countries defied expectations on Wednesday and lowered its output ceiling by 900,000 barrels a day to 24.5 million barrels starting in November .