The Tianjin Watch Factory formed a research team in 1965 that started to study the structure and technical parameters of over 140 watches made by Swiss, Japanese, German, Franch and Russian factories. The strength and weakness of these watches were listed, calculated and analyzed. Several new design drafts were drawn, submitted to experienced watch makers and sister companies for comments and suggestions.
In August 1966 the ST5 movement (27mm diameter, 3.8mm thick, 44 hour power reserve and an accuracy of +/- 30 seconds per 24 hours) was produced. Dong Feng was highly praised by consumers due to its reliability, bigger front face, nice-looking appearance.
As ST5 was born in the great cultural revolution (1966-1976) and was named Dong Feng, which translates into Eastern Wind. When the Tianjin Watch Factory started doing business across the borders of China, it was decided the name Dong Feng had too much political connotations and was changed into Sea-Gull, making Dong Feng disappear in 1973 after only eight years of existence.
The Chinese writing of Dong Feng on top of the dial is said to be the handwriting of Mao. The text Fang Zhen on the bottom of the dial means Shock Proof.