Concern over the health of ailing Emperor Hirohito dampened trading today on the Tokyo Stock Exchange, while the dollar firmed against the Japanese yen. The 225-share Nikkei Stock Average gyrated through the day over concern for Hirohito, whose condition appeared to stabilize today after setbacks over the weekend. The Nikkei lost 59.17 points, or 0.22 percent, to close at 27,330.95 in dull trading. Volume on the first section was a light 550 million shares. Traders said investors were reluctant to take large positions because of fears the market might close temporarily upon Hirohito's passing, leaving them unable to respond to financial markets overseas. In addition, many traders cited the psychological impact of uncertainty over the health of any major world figure. Hirohito has reigned for nearly 62 years. Monday was also the last day Japanese brokerages could trade on their accounts for the fiscal year ending Sept. 30, when most companies close their books. On the Tokyo foreign exchange market, the dollar closed at 134.73 yen, up 0.26 yen from Thursday's close, the last day of trading. It opened at 134.80 yen and moved in a narrow range of 134.66-134.85 yen. Dealers attributed the dollar's strength to a reaffirmation over the weekend among monetary authorities from seven major countries. The Group of Seven met in West Berlin and decided to continue to coordinate economic policies targeting stable exchange rates and containing inflation. ``Following the outcome of the G-7 meeting, the market took it as an indication there will be no market intervention by the nation's central bank at the current exchange rate level,'' said a dealer at a major commercial bank in Tokyo, speaking anonymously.