Calvin Choi Wai-chun (Chinese: 蔡蔚駿; born 1974/1975), also known by his pen name Fatmoonba (月巴氏), is a Hong Kong writer, film critic, and radio host.

[2] He developed a passion for wuxia novels at a young age and aspired to be a comic book artist, but abandoned that dream after scoring an F in visual arts on his Hong Kong Certificate of Education Examination.

[3] He began writing novels in Form 2, inspired by Ni Kuang's Wisely Series,[1] and won first prize in the 24th Youth Literary Awards [zh] in 1996 with his novella Teenager.

[10] Yan Ho-shun, reviewing for am730, called the collection "a valuable movie guide", praising Choi's personal and accessible style in dissecting classic films.

[12] Ching Kwan, reviewing for HK01, described the book as "a brilliant piece", praising its interesting selection of materials and Choi's candid, engaging writing style that provides insightful commentary on films.