The Nikkei went on wild ride on Friday, falling sharply from a two-month peak as volatility returned to Japan's benchmark stock index just before the key upper house of parliament election on Sunday.
Japan's stock market was down 1.6 percent at around 14,562 in mid-day Asian trade, having traded with a gain of more than 1 percent and a fall of as much as 2.7 percent.
Traders attributed the sudden bout of volatility, reminiscent of the swings that hit the Nikkei in late May, to profit-taking ahead of Sunday's election that sparked large scale selling of stock futures.
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"The move down took a lot of people by surprise, but what we've been worried about all week is the level of optimism in the market is way too high," said Ben Collett, head of Asian equities at Sunrise Brokers in Hong Kong, talking on CNBC Asia's "Cash Flow" about the sudden Nikkei sell-off.