Investigators said they were unsure of the attacker’s motives. But clues pointed to an isolated and increasingly troubled life, and no accomplices.

© Billy H.C. Kwok for The New York Times

In 1989, Gen. Xu Qinxian defied orders to crush the pro-democracy protests in Beijing. Now, leaked video from his court-martial is on YouTube.

Heng Guan fled to the United States and released rare video evidence of China’s clampdown. His supporters say that sending him to Uganda puts him at risk.

Beijing is pouring vast resources into fusion research, while the U.S. wants private industry to lead the way. The winner could reshape civilization.

She says Taiwan must embrace its Chinese heritage to avoid war. Her critics say she wants to steer the island into Beijing’s orbit.

President Lai Ching-te says the spending, which must be approved by the island’s legislature, would fund purchases of arms from the United States.

The Fujian, China’s most advanced carrier, went into official service this week. It brings the country closer to challenging U.S. naval dominance.

Ahead of a meeting with President Trump, China’s leader signaled that he is committed to competing in manufacturing and technology despite tensions with Washington.

China’s leader wants to weaken American support for Taiwan. But first he will want clarity about President Trump’s stance toward the island.