“Dànyuán 澹園” (Serene Garden) is the pen name of the anonymous Qīng-dynasty author of KR4k0267 Yànzi Jiān 燕子箋. No historical individual behind this pseudonym has been identified. The name follows the common practice of Qīng fiction writers adopting garden-studio names (zhāihào 齋號) as author attributions.