With at least one courtyard enclosed by four single-story buildings that face inward toward the open space, siheyuan represent the quintessential Chinese “courtyard houses.” Throughout China quadrangular courtyard structures come in many configurations, including many that are multistoried and others that have mere “skywells” with shafts of open space instead of broad courtyards. But siheyuan are best known because of their ubiquity in Beijing and other northern cities.