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period of rapid growth (especially Japan's period of rapid economic growth after WWII)
高度成長期の話を祖父からよく聞いた。
I often heard stories about the period of rapid economic growth from my grandfather.
高度成長期の経験が日本の産業政策の礎となった。
The experience of the period of rapid growth became the foundation of Japan's industrial policy.
高度成長期に整備されたインフラの老朽化が問題だ。
The aging of infrastructure built during the period of rapid growth is a problem.