Providing the market with a bit of optimism after a turbulent year, Tokyo share prices rebounded strongly Tuesday, the final trading day of 1997, on a bout of futures-related buying.

The 225-issue Nikkei average soared 483.52 points, or 3.3 percent, in the half-day session to end the year at 15,258.74.

But despite the rise, the yearend closing figures at the two exchanges were the lowest in 12 years.

Dropping steadily after peaking at its high for the year of 20,681.07 on June 16, the Nikkei average ended 1997 well short of its closing figure on the first trading day of the year, down 4,187.26 points -- or 21.5 percent -- for its second annual decline in a row.

Perhaps the biggest morale booster in the abbreviated session was an agreement struck in New York among several international banks to roll over South Korea's external debts, dealers said.

The festive mood at the exchange, however, was subdued by traders' worries about the coming year. A number of analysts are expressing caution in their outlooks for 1998, pointing to the ailing economy at home, the aftereffects of a record number of bankruptcies this year, rising unemployment and fears of contagion from the financial turmoil in Southeast Asia.

The market was stunned this year by major financial scandals uncovered at the nation's leading financial companies -- payoffs to a corporate racketeer, illegal compensation of market losses for favored corporate customers and "tobashi" stock-shuffling cases. Under tobashi trading, a brokerage house transfers securities held in the account of one client to that of another to prevent appraisal losses on equity holdings from being made public. The revelations reminded market players of similar financial scandals in 1991 that rocked the entire industry.

During the course of the year, individual investors were frightened away from the market and now account for the smallest portion of trading ever on the Tokyo, Osaka and Nagoya bourses. Foreign investors, who have been a major driving force on the market in recent years, turned net sellers of Japanese equities.

Then came reports on bankruptcies of financial institutions, including Hokkaido Takushoku Bank, the nation's 10th largest commercial bank, and Yamaichi Securities Co., the fourth largest brokerage house.

A series of economic stimulus measures announced by the ruling Liberal Democratic Party and Prime Minister Ryutaro Hashimoto in recent months have failed to make a floor for the falling market. Hashimoto's surprise announcement of a 2 trillion yen tax cut earlier this month gave the market a major lift, but the rebound soon fizzled out.

The gloom deepened when a report hit the market that a credit crunch forced trader Toshoku Ltd. out of business. The failure served as a reminder that super-stringent lending policies on the part of banks may pose a serious threat to businesses across the nation.