Natan Sharansky to intense political pressure from Ronald Reagan. Sharansky and three low-level Western spies (Czech citizen Jaroslav Javorský and West German citizens Wolf-Georg Frohn and Dietrich Nistroy) were exchanged for Czech spies Karl Koecher and Hana Koecher held in the United States, Soviet spy Yevgeni Zemlyakov, Polish spy Marian Zacharski and East German spy Detlef Scharfenorth (the latter three held in West Germany). The exchange took place on the Glienicke Bridge between East and West Berlin, which had been used before for this purpose. Sharansky immediately immigrated to Israel, adopting the Hebrew name "Natan" and eventually simplifying his surname to Sharansky.
Natan Sharansky High treason carried the death penalty. The following year, in 1978, he was sentenced to 13 years of forced labor. Sharansky spent time in the Lefortovo Prison in Moscow, followed by Vladimir and Chistopol prisons, where for part of the time he was placed in solitary confinement. His health deteriorated, to the point of endangering his life. Later he was detained in Perm 35, a post-Stalin-Gulag-type so-called "strict regimen colony" in Perm Oblast. He kept himself sane during solitary confinement by playing chess with himself, in his head. Sharansky appeared in a March 1990 edition of "National Geographic" magazine. The