* BOJ cuts rates, eyes asset buying in surprise move
* Nikkei moves away from 3-week low hit early in the day
TOKYO, Oct 5 (Reuters) - Japan's Nikkei average turned positive and rose 1.5 percent on Tuesday after the Bank of Japan in a surprise move cut interest rates and pledged to keep rates at zero until prices are seen stable.
The central bank also decided to set up, as a temporary measure, a 5 trillion yen ($60 billion) fund to buy assets ranging from government bonds and short-term government securities to commercial paper and corporate bonds, and will also accept another 30 trillion yen of those assets as collateral under a loan scheme.
The index moved further away from a three-week low hit earlier in the day when it was pressured by falls on Wall Street and cautious investors took a wait-and-see approach before the BOJ decision.
"It was an utterly surprising and bold move. The BOJ has sent a favourable message to the markets, which had been expecting it to take only small, gradual steps," said Seiji Shiraishi, chief economist at HSBC Securities Japan.
"Still, the BOJ's move is unlikely to impact the overall economy much even though the yen weakened briefly, as the root of the problems lies in the weakness of the U.S. economy."
The benchmark Nikkei gained 137.10 points to 9,518.16, after falling in the morning to as low as 9,332.19, its lowest since Sept. 15.
The broader Topix added 1.3 percent to 833.12.
The dollar jumped against the yen after the BOJ announcement. The greenback was at 83.67 yen, above a 15-year low of 82.87 yen set just before Japan intervened in the currency market the first time in six years on Sept. 15.
Exporters jumped, with Sony Corp rising 0.9 percent to 2,589 yen and Kyocera Corp climbing 2 percent to 8,270 yen. (Reporting by Aiko Hayashi; Additional reporting by the Tokyo newsroom; Editing by Chris Gallagher)