Nikkei sharply plunged after a four- day winning streak on Friday, as investors locked in gains while cautiously awaiting the decision on Tokyo\'s bid to host the 2020 Olympic Games and the outcome of key U.S. jobs data.The 225-issue Nikkei Stock Average closed down 204.01 points, or 1.45 percent, from Thursday at 13,860.81.The broader Topix index of all First Section issues on the Tokyo Stock Exchange shed 10.02 points, or 0.87 percent, to 1,147. 82.Decliners were led by real estate, fishery and forestry and consumer finance companies, while gainers included steel, sea transport and mining sectors.The turnover was about 1,709.2 billion yen (about 17.13 billion U.S. dollars).