Gonggan 21s is a cafe in a residential area near Seocho Station in Seoul that serves specialty coffee and simple desserts. It brews single-origin beans, including Yemeni beans, by hand drip and provides explanations of the beans. The cafe occupies a renovated two-story house with tables and a large window that lets in daylight, including seats by the window on the second floor. Prices are high, and the satisfaction does not match them.