The Bamboo Curtain is a Cold War euphemism for the political demarcation between the Communist and non-communist states of East Asia, particularly the People's Republic of China. It is used less often than the eponymic "Iron Curtain" because the former shifted frequently. The term was less often applied to the Korean Demilitarized Zone dividing North and South Korea and the flexible Southeast Asia border between Communism and the West (here referring to the forces aligned against Communism during the Cold War).
During the Cultural Revolution in China, the Chinese authorities put its sections of the Curtain under a lock-down of sorts, forbidding entry into or passage out of the country without explicit permission from the Chinese government. Many would-be refugees attempting to flee to capitalist countries were prevented from escaping in this manner.
The term "Bamboo Curtain" was used less often than the term "Iron Curtain" in part because while the latter remained relatively static for over 40 years, the former shifted constantly and was somewhat more porous. It was also a less accurate description of the political situation in Asia because of the lack of cohesion within the East Asian Communist Bloc, which ultimately resulted in the Sino-Soviet split; The Communist governments of Mongolia, Vietnam and later Laos were allies of the Soviet Union, while Cambodia's regime of Pol Pot was loyal to China. Shortly after the Korean War, North Korea swore allegiance to neither the USSR nor China (this refusal to take sides by North Korea continues today, though now in the opposite direction: North Korea proclaims solidarity with both Russia and China).
Improved relations between China and the United States during the later years of the Cold War rendered the term more or less obsolete, except when it referred to the Korean Peninsula and the divide between allies of the US and allies of the USSR in Southeast Asia. Today, the term is more often used to refer to the tightly-guarded borders of Burma, whereas DMZ, when used in a political sense, is generally used for the demilitarized zone separating North and South Korea.