Tokyo stocks dropped sharply Thursday, as a stronger yen prompted selling of exporter issues and energy-related shares were unloaded after U.S. oil futures hit a five-month low. The 225-issue Nikkei Stock Average ended down 587.59 points, or 1.76 percent, from Wednesday at 32,858.31. The broader Topix index finished 27.29 points, or 1.14 percent, lower at 2,359.91. On the top-tier Prime Market, decliners were led by marine transportation, mining and electric appliance issues.