The Nikkei index closed Friday at a fresh 20-year low, battered by sales of technology stocks that were pushed down by Sony's bearish earnings outlook released the previous day.

The 225-issue Nikkei average plunged 155.07 points, or 1.97 percent, to close at 7,699.50 -- its lowest mark since Nov. 16, 1982, when it closed at 7,698.30.

The broader Topix index of all first section issues on the Tokyo Stock Exchange slipped 12.42 points, or 1.56 percent, to 782.03.

Technology shares fell victim to heavy selling after Sony released a weaker-than-expected earnings estimate Thursday for the business year through March 31. Sony drew heavy selling, scoring its maximum daily limit drop of 500 yen to 3,220 yen.

"It is not yet certain whether the weak forecast resulted from its own reasons or deterioration of the macroeconomy," said Masatoshi Sato, senior strategist at Mizuho Investors Securities Co. "But (the forecast) raised uncertainties about the future and gave investors enough reason to refrain from buying technology shares."

International blue chips were also hit by a re-emergence of geopolitical concerns surrounding North Korea after reports that Pyongyang admitted during talks with the United States and China in Beijing this week that it has nuclear weapons and has started reprocessing spent fuel rods.