Huaigan

Huaigan (懷感; c. 7th century) was a Chinese Buddhist monk who was the leading student of the Pure Land patriarch Shandao (613–681) and key systematizer of Chinese Pure land thought. The Japanese Pure Land teacher Hōnen designated Huaigan as the fourth patriarch of Pure Land Buddhism in the Jōdo-shū tradition.

According to Ming-wood Liu "his representative and only extant work, the Shì Jìngtǔ Qún Yí Lùn [釋淨土群疑論, Treatise Explaining a Number of Doubts on Pure Land, T 1960], was a brilliant attempt at Pure Land apologetics, providing replies to virtually all the criticisms which had been raised against Pure Land ideas and practices."

Huaigan's work remained influential on other Chinese figures like Yongming Yanshou and the Tiantai monk Zunshi (964-1032 C.E.). Huaigan was also important to Japanese Pure Land authors like Genshin.