Pen of Cam Chi, student of Thien Loc

(photo source: blackberryvietnam.net)

Vu Toai (also named Vu Diem) was born in Thien Loc(1) district. During his study at Thang Long (2), Vu Toai and Nguyen Duy Ky, Nguyen Ba Lan, Tran Danh Tan were named "Trang An's four tigers: Ki Lan Tan Toai" (3). Among these four tigers, Vu Toai is the best one. At that time, the people had a proverb: "Pen of Cam Chi, student of Thien Loc" (4). After his success, Vu Toai opened the class for teaching and he was named "teacher of heaven". 

Annotation:

(1) Thien Loc: today belong Can Loc district, Ha Tinh province.

(2) Thang Long: capital of Dai Viet, today belong Ha Noi.

(3) Trang An: other name of Thang Long

(4) Cam Chi: place of Thang Long where the best pens were bought. The proverb in vietnamese is "Bút Cấm Chỉ, sỹ Thiên Lộc".