Asia mixed; Nikkei hits 8-week high on weak yen

Asian stocks were mixed on Thursday but sentiment was underpinned by Federal Reserve Chairman Ben Bernanke, who confirmed there was no set timeline for winding down U.S. monetary stimulus.

Japan's Nikkei index outperformed to hit an eight-week high, while Australia's S&P ASX 200 ended just below the 5,000 mark. But South Korea's Kospi eased 0.6 percent and the Shanghai Composite hit a one-week low.

(Read more: Has Bernanke perfected balance between hawks and doves?)

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The Bernanke effect

In his semiannual monetary report to the House Financial Services Committee on Wednesday, Bernanke reiterated the central bank's plan to start paring back bond-purchases later this year, but said that could change if the labor market outlook darkens or if inflation does not seem to be rising toward the Fed's 2 percent goal.

"I think markets are going to be more volatile for the next 12-18 months as the Fed prepares markets for the exit. The question is, can they manage equity markets where they are and keep the economy going?" said Kumar Palghat, managing director at Kapstream Capital.

Bernanke heads back to Capitol Hill on Thursday to testify before the Senate Banking Committee.

Nikkei rallies 1.%

The Japanese yen weakened to 100 per dollar, propping up exporter stocks and leading the index to its highest levels since May 24. Sharp jumped nearly 4 percent while telco carrier Softbank also rose 4 percent on news of a joint venture project with U.S. firm Bloom Energy tosupply green energy to Japanese corporations.

Still, the index is down 7 percent since hitting a five-and-a-half-year peak of 15,942 in May.

(Watch now: Too much enthusiasm for Japan markets: Pro)

A Reuters survey of sentiment among Japanese manufactures eased in July for the first time in eight months over worries of a slowdown in China. The data marks a big step down from a two-year high in June and highlights complaints that the effects of Prime Minister Shinzo Abe's stimulus policies have yet tobe seen.

Shanghai 1% lower

Mainland property stocks were in focus for China's benchmark stock index after data showed average new home prices for the month of June jumped 6.8 percent year-on-year, higher than a forecast by analysts polled by Reuters for a 6 percent gain.

Developers slumped in reaction as investors worried about more property curbs to tame price rises, helping push the Shanghai Composite to its lowest level in a week. Gemdale led declines by 3 percent while both Vanke and China Merchants Property eased over 2 percent each.

(Read more: The long game: Why a China slowdown isn't scary)

Sydney adds 0.2%

Australia's benchmark index briefly crossed the key 5,000 level in afternoon trade before paring its gains. Banking stocks underpinned index gains with a 1 percent rally in National Australia Bank and Westpac.

The nation's largest independent oil firm Woodside ended flat after announcing a 0.6 percent drop in second quarter production. Meanwhile, rival Santos rallied 2.3 percent.

(Read more: Weak China, robust dollar 'toxic mix' for commodities)

The next barrier for the benchmark index to cross will be 5,012 points, which would mark a new a one-week high.

Kospi slips 0.6%

South Korea's benchmark index retreated from the previous session's one-month high of 1,894, weighed down by blue-chip tech stocks as the yen renewed its pace of declines. The index traded at a 66-point discount to it's 200-day simple moving average (SMA) of 1,946.

Samsung Electronics tanked 2 percent while flat-screen maker LG Display lost 3 percent. After the market close, LG Display reported a 53 percent rise in second-quarter profit, which is likely to boost it's share price at Friday's open.

(Watch now: How to invest intelligently in the tech space)

Shares of Asiana Airlines eased 1 percent after two passengers aboard the Boeing 777 flight that crash landed in San Francisco earlier this month sued the Korean airline.

By's Nyshka Chandran. Follow her on Twitter @NyshkaCNBC