The extended absence of Chinese Vice President Xi Jinping, just weeks before he is expected to be named China's top leader, is nothing new in the Communist Party's opaque, secretive political culture. Top leaders have vanished amid power struggles and health problems before only to resurface — or not. Here is a sample:

THE CLOSEST COMRADE: Chairman Mao Zedong's "closest comrade in arms" and hand-picked successor, Lin Biao dropped from view in September 1971 amid the radical turmoil known as the Cultural Revolution. Turns out he had died. The government started telling ordinary Chinese about his death only two months later; some accounts say it was 10 months later. Lin's death remains shrouded in mystery. The official version says he and his family died in a plane crash in Mongolia attempting to flee to the Soviet Union after plotting to assassinate Mao and stage a coup. Other accounts say Mao's supporters did Lin in first.

THE PARAMOUNT LEADER: After authorizing the military crackdown that ended the 1989 Tiananmen Square democracy movement with untold deaths, paramount leader Deng Xiaoping was shown on state television congratulating martial law troops on June 9. Then he stayed out of the public eye for more than three months. Deng, 85 at the time, had retired from most of his positions but was still regarded as the pre-eminent power in a divided party. His disappearance triggered reports he was ill or near death. He resurfaced in September looking tan and healthy as he met a Nobel Prize-winning Chinese American physicist. During his absence, he met in secret with an envoy sent by U.S. President George H. W. Bush to stabilize U.S.-China ties. Deng died in 1997.

PURGED REFORMER: At the height of the student-led democracy movement in 1989, party chief Zhao Ziyang went to Tiananmen Square on May 19 and tearfully appealed to student hunger strikers to go home, saying "I came too late." The next day, the government declared martial law and Zhao disappeared. After the June 3-4 military crackdown on protesters, speculation was rife that Zhao had been stripped of power. His fate became known more than a month later, when the party fired him. Purged for supporting the demonstrations, Zhao lived in Beijing under house arrest until his death in 2005. He was occasionally spotted playing golf in the suburbs and touring the provinces, though state media never reported on him.

THE HARDLINER: When Premier Li Peng suddenly canceled a meeting with the Philippine president in 1993, the excuse the government gave was that he had a cold. Over the next four months, Li made only two public appearances. At one of them he confessed to a "minor heart condition." When he resurfaced in August, it was on the front page of newspapers, standing in swim trunks with his hands on his hips. China scholars later wrote that Li had suffered a heart attack. Some accounts say it was preceded by scathing criticism from party elders. Li outlasted his rivals, clinging to power until 2003 after 16 years in the leadership.

THE ALLY: Vice Premier Huang Ju lectured Chinese bankers in early 2006 on the importance of government control over state banks. Then he dropped from sight. Nearly two months passed before a Chinese official said vaguely that Huang had been unwell and was convalescing in a hospital. Media were banned from reporting on his condition. Because of his illness, Huang, a key ally of former Chinese President Jiang Zemin, had been expected to retire in the fall of 2007. He died four months earlier. The official announcement of his death gave no cause, though reports say he had pancreatic cancer.