Share prices took the largest drop of the year today on the Tokyo Stock Exchange, and the dollar fell sharply against the Japanese yen. The Nikkei Stock Average of 225 selected issues, a 251.67-point loser the day before, plunged 513.09 points, or 1.89 percent, closing at 27,149.03 points. It was the largest one-day decline of the key index since December 26, 1987, when the Nikkei fell 587.50 points. Stock brokers attributed the decline purely to the internal reasons. They said steel and shipbuilding shares, which had supported the market over the past few weeks, finally gave way and led to a decline across the board. Nippon Steel, one of the largest shares on the exchange, had risen from the 400's to 750 yen in less than two months, but lost 54 points today. ``I can't see any outstanding reason why shares, especially steel shares, fell this much today,'' said Ichitaro Watanabe, a broker at Nikko Securities Co. ``The market seems to have entered a transitional stage. The 500-point drop is a result of an adjustment made for the transition.'' Another stock broker said the plunge without apparent reason indicated steel and ship building shares can no longer sustain the market. ``The market as a whole was not in a good mood in the last two weeks except for steel and shipbuilding shares,'' said Keiichi Nishida of Kidder Peabody. ``Today's plunge indicates the end of the steel-led market. Investors have to find other shares they can count on.'' In the foreign exchange market, the dollar, which gained 1.75 yen Monday, closed at 133.85 yen, down 1.30 yen from Monday's close. After opening at 134.30 yen, it traded in a range of 133.70-134.38 yen. Currency dealers said early morning speculation on whether the Bank of Japan would intervene in the market and sell dollars was the major cause of the currency's decline. ``The speculation led to a one-sided selling of the dollar,'' said an exchange dealer at a major U.S. bank in Tokyo, speaking on condition of anonymity.
