Ten minutes’ walk from my flat, an iron bridge, Bösebrücke, spans the railway tracks that once divided East and West Berlin. One of the few checkpoints in the Berlin Wall used to stand in the middle of the bridge. On the approach, a discreet memorial shows black-and-white photographs from thirty years ago. On 9 November 1989, border guards of the German Democratic Republic (GDR) yielded to throngs of East Berliners and the crossing was opened to the jubilant masses. Free travel was permitted for the first time since 1961. The GDR’s strategy of jailing its own citizens had finally proved a failure. In under a year, the Soviet satellite state had merged with the Federal Republic and vanished forever.

I visited the GDR just once. In the summer of 1987, at the age of fourteen, I accompanied my West German grandparents on a visit to my grandfather’s buddy from his days in the Wehrmacht who had become a bigwig in the GDR’s Ministry of Science. For a UK-raised, US-dwelling teen subsisting on Kerouac, Häagen-Dazs and Star Wars, five days in Real Existing Socialism were akin to a holiday in monochrome. After hours on an autobahn, the potholes of which hadn’t been filled since the fall of the Third Reich, we arrived in Potsdam, outside Berlin, where our hosts gratefully accepted our gifts of capitalist toilet paper and house paint. As tourists, we registered at a police station, a crumbling building full of curmudgeons in stiff uniforms. I recall being told that Potsdam had run out of ice cream. The whole city. So much for the centrally planned economy.

The centre of East Berlin was a concrete jungle populated by a few humans and sputtering Trabants. On the day we arrived, we had a stodgy schnitzel lunch. I was dumbfounded by the view of the Berlin Wall from the eastern side. It seemed inconceivable that in under three years people would be dancing on the ruins of the hideous ‘anti-fascist protection barrier’.

Another side of 1980s East Berlin eluded me then. In Prenzlauer Berg – where I live today – disaffected artists and dissidents hunkered down in draughty 19th-century tenements. The mavericks claimed what freedoms they could within the narrow parameters of the dictatorship, putting on illegal punk concerts and fashion shows. One of the most audacious projects was the creation of an underground magazine, radix-blätter, East Germany’s contribution to the samizdat literature found across the Eastern Bloc. A new book, Fenster zur Freiheit, by the journalist Peter Wensierski sheds some light on these ventures.

The official literary scene was a miserable affair. There was no law limiting speech, but publishers’ in-house censors scoured manuscripts for politically risqué writing. Sometimes only sections were deleted. Eight passages, for instance, were excised from Christa Wolf’s 1983 novel Cassandra. Enterprising readers would glue smuggled photocopies of the missing section from the uncensored Western edition into theirs as an act of rebellion. Communist Party officials sometimes blocked publication of books altogether, as was the case with the German translation of Primo Levi’s If This is a Man, which was thought to portray communist prisoners in Auschwitz in an unfavourable light.

In 1985, Stephan Bickhardt, a discontented East German theology student, visited Prague, where locals introduced him to Czech underground magazines. In the GDR, banned books were smuggled in from West Germany, so there was little underground publishing. Bickhardt became convinced that a homegrown publication was needed to link the isolated strands of the GDR dissident scene – artists, writers, church peaceniks and environmentalists. With his friend Ludwig Mehlhorn, Bickhardt began publishing on paper illegally donated by a printer within the Catholic Church, using an old press smuggled in by a West German Green Party MP.

The name radix-blätter alludes to a poem by Paul Celan, ‘Radix, Matrix’, in which the Jewish poet addresses his parents, who perished in a Nazi concentration camp. Bickhardt and Mehlhorn felt society’s issues had to be addressed at the root, hence radix (Latin for ‘root’ or ‘origin’). So taken were they by Celan that they devoted the entire first issue to him. Since the Holocaust, no single poet had plumbed the abyss of German history as he had. My skin crawls when I read the famous line ‘Der Tod ist ein Meister aus Deutschland’ (‘Death is a master from Germany’) in the poem ‘Death Fugue’, perhaps the most sorrowful piece of writing about the Holocaust ever produced.

Last month, I visited the Robert Havemann Archive, which contains documents relating to the East German opposition, to peruse original copies of the magazine. The archive is housed in the former Stasi headquarters in Berlin. Holding the yellowing A4 pages in my hands inside this behemoth of a building, the precariousness of free speech felt tangible. The debut issue, titled ‘Shadow Closures’, contains twelve essays, each addressing a different Celan poem. Celan’s oeuvre provided a springboard from which to tackle taboo subjects, such as the continuity between Nazi and communist Germany and the refusal to acknowledge the consequences of totalitarianism. In his introduction, ‘Interrupted Silence’, Bickhardt raises the question of his grandfathers’ guilt in the war: ‘Were they also underway in the battle against other peoples?’ In the GDR, such matters weren’t talked about. Officially, all the Nazis had fled to the imperialist West.

Some issues contained experimental poetry – outbursts lamenting the claustrophobia, paranoia and melancholia pervading the GDR. The poems are packed with puns, onomatopoeia and other untranslatables, but occasionally a crystal-clear phrase emerges from the word stream: ‘i hate/germany/your past/this is a bad start’ (these words were written by someone called Gino).

By 1988, people were speaking more openly in churches and elsewhere. The writing was on the wall for communism in eastern Europe. In an issue published that year called ‘Patterns’, radix-blätter dealt with authoritarian power head-on. In one piece, ‘Language that writes and thinks for you’, Dorothea Höck discusses the toxicity of state propaganda: ‘In our society children already learn it. In all public spaces, the language of bureaucracy or of ideology is spoken – everywhere that our state has the power to dominate the actions and thoughts of people, and, in the case of objection, to impose effective punishment.’ Propaganda, she writes, has redefined fundamental concepts, resulting in an ‘impoverishment of the perception of reality’. She quotes the GDR Taschenlexikon für Zeitungsleser (a paperback guide to terms used in the media put out by a party-controlled publisher), in which ‘freedom’ is defined as ‘the level of recognition and practical controllability of objective legitimacy in nature and society. Freedom exists in people’s understanding of objective necessity that is only possible in socialism.’ It gets worse. As a supreme example of communist doublespeak with a Nazi aftertaste, Höck tells us that the lexicon defines ‘Holocaust’ as ‘a term that means genocide and is sometimes used to describe the Israeli-imperialist extermination campaign against the Palestinians’. There is no mention of the Nazi death camps.

More than a lovingly produced dissident journal, radix-blätter was a node in a network more social than those that bear the name today. Each issue emerged out of long workshops and seminars. In total, about 130 undesirable writers were published in its pages. Some issues were all poetry and fiction; others contained essays on statecraft and possible futures. Copies were handed out at readings, political meetings and church events. Although the Stasi was everywhere, it never found the printing press in Bickhardt’s parents’ house in an East Berlin suburb and no arrests were ever made in connection with radix-blätter.

On 9 November 1989, the whole oppressive state edifice collapsed in one fell swoop. East Germans hammered at the Wall and watched it disintegrate. When Lenin said, ‘there are decades where nothing happens; and there are weeks where decades happen’, he surely did not have the crumbling of his own dream in mind.

Nowadays, the New Right paint themselves as rebels crusading for free speech in a dictatorship of the politically correct. The populist party Alternative für Deutschland finds fertile soil in Germany’s east among people who never took to heart the message of samizdat: free speech is part of a democratic package that includes fundamental human rights. The result of this ignorance is perverse rhetoric. The septuagenarian AfD politician Alexander Gauland has called the Nazi period a little bit of ‘bird shit in more than a thousand years of successful German history’.

As I was writing this in the grim old Stasi HQ, my phone delivered news of a shooting outside a synagogue in the eastern city of Halle. Two people were killed. If the assailant had breached the gates, seventy worshippers marking Yom Kippur might have died.

In front of me is a faded radix page with a poem by Rainer Schedlinski:

You take bad routes
someone has counted your steps in the snow
& this silent knowledge
is mother & murderer
of things & all these
silent executions
are like an eternal cult
of a prolonged past.