The 225-issue Nikkei Stock Average lost 543.15 points, or 1.82 percent, from Friday to 29,248.90.
The broader Topix index of all First Section issues on the Tokyo Stock Exchange, meanwhile, dropped 22.25 points, or 1.11 percent, at 1,989.96.
Transportation equipment, insurance and electric appliance issues comprised those that declined the most by the morning break.
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