Erhai congtan 洱海叢談 "Various talks about Lake Erhai" is a geographical description of the province of Yunnan written during the early Qing period by the Buddhist monk Tonggui 同揆, who lived himself in Mañjuśrī Monastery (Wenshu Si 文珠寺) in Dali 大理.
He came to Yunnan in 1681, with the imperial armies suppressing the rebellion of the Three Feudatories, and left this province again in 1686 to his home in Changzhou 長洲 (Cheung Chau, an island close to Hong Kong). The short book about Yunnan was finished two years later. It describes the region of Dali with Lake Erhai 洱海 and Mt. Cangshan 蒼山 and its history, beginning in the Han period 漢 (206 BCE-220 CE), when the kingdom of Dian 滇 was first incorporated into the Chinese empire. Apart from geographic information, the text describes the customs of the local population.