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castle tower; keep; donjon
天守閣に登って景色を楽しんだ。
I climbed the castle tower and enjoyed the view.
戦国時代の天守閣は軍事的な目的で建てられた。
Castle towers in the Warring States period were built for military purposes.
修復工事を経て、天守閣は往時の壮麗な姿を取り戻した。
After restoration work, the castle tower regained its former splendor.