Two distinct senses with the same characters. (1) Geopolitical:
闭关锁国 (bìguān suǒguó) — the Qing dynasty's "closed-door" foreign policy of restricting trade with the West, often blamed for China's 19th-century weakness. (2) Religious/figurative: a Chan (Zen) Buddhist monk withdraws into a cell for weeks or months of solitary practice. Modern usage extends this metaphorically — students or writers say
闭关 to mean "I'm going dark to focus."
