Part of the filming took place in Cuba.
Prototype of "Trianon" - Alexander Ogorodnik was real employee of American Department of Ministry of Foreign Affairs in USSR.
Prototype of Vitaly Slavin was Yulian Semyonov's friend Vyacheslav Kevorkov, KGB general.
Initially, Tatyana Lioznova, known for the film "Seventeen Moments of Spring", was supposed to stage the film. However, the author of the script, Yulian Semyonov, spoke out against her.