Americas's challenges.

• Position: ASIA 2013 - China economy, Afghan troop withdrawal and Japan nuclear energy - Brief article

CHINA

With a population of 1.3 billion and a booming manufacturing industry making everything from jeans to big-screen TVs, China has surpassed Japan to become the world's second-largest economy behind the United States. China appears likely to overtake the U.S. in the years ahead.

AFGHANISTAN

After 11 years of war that began in the wake of the Sept. 11, 2001, terrorist attacks, the U.S. says it plans to withdraw all combat troops by the middle of 2013. Officials hope a deal can be brokered with Taliban insurgents to prevent the country from slipping back into chaos.

JAPAN

It may take years for Japan to fully recover from a devastating earthquake and tsunami in 2011. Meltdowns at several damaged reactors have sparked a backlash against nuclear power, which had provided a third of Japan's electricity. It also raised fears about...