It was later renovated by his son, Tokugawa Mitsukuni who named it "Korakuen" with the advice of the Ming Confucian scholar Zhu Zhiyu and inspired by descriptions of Yueyang Tower in Chinese literature and poetry.

The gardens cover an area of more than 70,000 square meters and are planted with plum blossoms, cherry blossoms, azaleas, irises, and other flowering plants, and contain ponds and monumental stones.

The gardens were the property of the Mito Tokugawa until 1869, when the final daimyō of Mito, Tokugawa Akitake surrendered the property, together with his mansion, to the new Meiji government.

The new government assigned the property to the Ministry of the Army, who constructed an artillery factory on a portion of its grounds.

In 1923, it was designated as a National Historic Site and also as a Place of Scenic Beauty with the designations promoted to "Special National Historic Site" and "Special Place of Scenic Beauty in 1952".