Final answer:
The 'three bitter years' refer to the period following the failure of China's Great Leap Forward, a policy that caused a significant famine and the deaths of millions, leading to political and economic repercussions.
Step-by-step explanation:
The "three bitter years" were recalled by the Chinese government after the failure of the Great Leap Forward policy. This was a critical period in Chinese history, where an ambitious campaign led by the Chinese Communist Party aimed to rapidly transform China from a largely agrarian society to a socialist society through rapid industrialization and collectivization. The policy resulted in a massive decline in agricultural production, leading to a catastrophic famine and the deaths of tens of millions of people. The profound impact of the Great Leap Forward led to political repercussions within the Chinese Communist Party, and its failure caused the Chinese government to reconsider its approaches to economic planning and reforms.