Shares were mixed in Asia Thursday on quiet trading marked by rumors.

Japan's Nikkei led gains again, climbing 415 points, or 3.03%, to 14,124.47, after the U.S. dollar broke the crucial 105 yen band. The yen ended the day at 105.21 vs. the dollar, from 104.89 previously. In Hong Kong, the Hang Seng rose 135 points, or 0.6%, to 24,383.99, and in China the Shanghai Composite Index lost 58 points, or 1.7%, to 3401.44.

"The Hong Kong and other regional markets are remaining pretty much technical these days, with a lack of companies reporting and constant reminding on the state of the U.S. housing market," says Steven Wong, a trader at Daiwa Bank in Hong Kong. "There is an upside bias likely with obvious beneficiaries being airlines and exporters after crude's drop."

The days news flow was dominated by a rumor that North Korean leader Kim Jong Il has been assassinated. The rumor of the assassination, which has been flying around the region quietly for a few days, gained further attention when South Korean internet site News Hankuk reported an unnamed Chinese official saying that Kim Jong Il has been assassinated "with ninety percent certainty." The article states that the President of North Korea was killed on a road near Pyongyang between 7 pm and 8 pm local time, or 6 am and 7 am EST, on May 26.

The South Korean government denies the rumor, while North Korea's state-owned news organization KCNA says that the President has been busy visiting textile plants and watching performances.

South Korea's market, known as the Kospi was the second-best performing index in the region Thursday, rising 36 points, or 2%, to 1841.22. Market participants attributed the rise in stocks mostly to exporters such as Posco ( PKX), which benefits from a stronger dollar, rather than to the rumor.

Posco, Korea's largest listed steelmaker and a reputed national favorite of Warren Buffet, jumped 3.5%, to 569,000 won.

In Hong Kong, shares in China Life Insurance ( LFC) gained 0.5%, to HK$31.10, after investors cheered a rumor that the insurance giant may purchase local Hong Kong bank Wing Lah Bank. Local news outlets reported that China Life has approached the Fung family, the largest shareholders in Wing Lah, about a possible acquisition.

Meanwhile, Dah Sing Banking Group, another local chain, says it has been approached as an acquisition target by "Chinese banks and foreign banks". Dah Sing leapt 4.1%, to HK$16.24.

An investigation being launched into fraudulent warrant dealing in Hong Kong sent shares of Hong Kong Exchanges ( HKXCF) 1.6% lower, to HK$134, despite the uptick in the index. Hong Kong Exchanges is generally considered a proxy for the Hang Seng, and usually moves in the same direction of the market. Turnover in Hong Kong was sluggish, at $64.09 billion ($8.21 billion).

Among telecoms, China Mobile ( CHL) staged its first proper rally this week after having fallen more than 11% since the announcement of industry restructuring in China. China Mobile added 1.5%, to HK$114.60. China Telecom ( CHA), which is currently suspended from trading, said it will partner with U.S. CDMA developer Qualcomm ( QCOM) to develop the mobile business it is set to acquire from China Unicom ( CHU). Shares in China Unicom are also suspended from trading.

Korean telco SK Telecom ( SKM) said that it has agreed to join a consortium, including giant China Mobile, which will invest in $1 billion in the construction of a technical research center in Beijing. SK Telecom lost 0.7%, to 20,300 won.

Among commodities, oil fell to $130.41 in Singapore trading vs. $131.03 the day before. Gold was stronger however, up $2.84, or 0.3%, at $903.68 on inflationary concerns.

In a research note titled "Out of Oil Stocks," published Thursday, Sean Darby, head of Asian strategy for Nomura Bank in Hong Kong, wrote that investors should stay away from companies such as PetroChina ( PTR) and CNOOC ( CEO).

"With the oil futures market moving from backwardation to contango, rising G7 bond yields and changes to fuel subsidies in emerging markets, we would expect spot oil prices to correct," wrote Darby. "Aggressive portfolios should consider shorting oil stocks."

PetroChina gained 0.8%, to HK$10.74, but CNOOC, a purely upstream developer, plunged 3.2%, to HK$13.74.

In Japan, the Tokyo stock exchange announced that it is revising the ticker sizes of companies trading on the local exchange down by 90%. For example, Canon ( CAJ), which trades at 5540 yen, will now trade in blocks of 100 yen vs. blocks of 1000 yen previously. Any stock which trades at a share price of over 1 million yen will not trade in blocks of 1000 yen vs. 10,000 previously.

"So volumes will increase, but algorithmic engines will have to work harder," says Gavin Parry, a director of Helmsman Global Trading in Hong Kong. "Given the amount of share splits we are seeing as well,the hope is that we don't get the bottle neck situations from a few years ago."

When volumes in Japan have increased previously, the Tokyo stock exchange has frozen as it has struggled to handle the higher trading capacity, adds Parry.

Japanese exporters are faring well, and many market participants are now looking for the Nikkei to head towards 15,000, if the dollar continues its ascent. Canon rose 4%, to 5540 yen, and Sony ( SNE) added 3.7%, to 5080 yen.

Elsewhere in Asia, trading was mixed. Taiwan's Taiex climbed 0.2%, to 8684.92, and India's Bombay Sensitive Index lost 1.3%, to 16,316.26.

Be sure to check out the Far East Portfolio at Stockpickr.com to find out which Indian and Chinese companies are making big moves and announcing major news.

Daniel M. Harrison is a business journalist specialising in European and emerging markets, in particular Asia. He has an MBA from BI, Norway and a blog at www.theglobalperspective.biz. He lives in New York.