《The Gateless Gate》 is a large-scale installation by Choi Jeong Hwa, first presented at APAP5 (2016). It was crafted from recycled materials including steel, formwork, and furniture donated by citizens or collected from the streets. This substantial structure, with its vast interior, literally translates to "a space without a door," symbolizing a state of enlightenment. By transforming everyday materials into art, the artist created an accessible artistic experience that resonates with everyone.

Following this, at APAP6 (2019), a project was launched to reorganize and expand the bookshelf space within the artwork. Moving away from the previous chronological classification, call numbers were assigned according to the Korean Decimal Classification (KDC), and extensive research on recent publications was conducted to provide a richer collection of resources. A new search system was also developed to enhance user convenience, and a conservation bookshelf was added to the Open School, making it accessible even in Pyeongchon.

Furthermore, a special thematic category focused on Anyang was newly established, and the children's bookshelf was expanded, strengthening its identity as a public art library. Special book curation, operated three times under the overarching theme of "Coexistence City," provided citizens with an easier avenue to engage with public art discourse.