riting about the protest movement in Hong Kong, I began to notice the absences everywhere I went. A moving patchwork of white, black and grey squares decorated walls and pavements, as more and more protest slogans were erased from the public gaze. Now, with Beijing’s enactment of national security legislation in Hong Kong, that void has suddenly gaped wider, swallowing words, ideas, open discussion, and even people from public view. The legislation bans secession, subversion, terrorism and collusion with foreign forces. The first sight of it for Hongkongers was the moment that it came into effect on Tuesday at 11pm, ahead of the annual 1 July protest march, which itself had been declared illegal. In one fell swoop, the new law pushed through many of the changes most feared by Hongkongers, by giving mainland legal bodies jurisdiction over some cases inside the territory, allowing the mainland security services to establish offices in the territory, permitting rendition to China and implementing national security education in local schools. By Thursday night, the government had announced that the most popular protest slogan – an eight-character Chinese phrase translating as “Liberate Hong Kong, Revolution of our Times” – violates the legislation as it “connotes ‘Hong Kong independence’”. This phrase has been chanted at every march by almost every attendee. Since that moment, those Chinese characters began disappearing from social media, replaced by initials (GFHG, SDGM), numbers that serve as Cantonese homophones (3639 0242), symbols or geometric representations of the characters. One protest consisted of eight people standing in the street in two groups of four, each holding up a blank piece of paper. In just a few days, those words have already become unspeakable. By Saturday, Hong Kong’s justice secretary, Teresa Cheng, was warning people not to test the national security law by using the slogan. The previous day a 24-year-old man had been charged with inciting secession because his motorbike was adorned with a flag bearing the motto. He was also accused of terrorist acts for driving his bike into a group of policemen. Overnight Hong Kong’s reality has become Kafkaesque, even Pythonesque, were it not for the real risk of breaking a law that could carry a sentence of life imprisonment. Even the act of alerting Hongkongers to newly illegal acts has become fraught. The government broadcaster, RTHK, used asterisks in its tweets (variously “L******* Hong Kong!” and “Liberate H*** K***!”), while the founder of Hong Kong Free Press, Tom Grundy, said he expected legal and bureaucratic terrorism designed to drain the website’s resources. The surrealism was heightened by the police detention of an overjoyed soccer fan suspected of inciting independence after shouting “Long live Liverpool!” to celebrate the team’s Premier League win. He was later released. Among 370 people arrested on 1 July, at least 10 were detained for violating the new legislation, including three women for possessing offensive materials. Among these, it emerged from police photos, was a sticker emblazoned with the word “Conscience” – causing one netizen to comment that in a country without conscience such a sticker surely amounts to secession. The lack of clarity surrounding the offences, combined with such arbitrary application, has left the population dazed. Libraries have already begun pulling books by certain pro-democracy figures from the shelves for review, signalling a looming assault on freedom of information. In the decade I spent reporting from China, I found that the laws were often less black and white than I’d imagined. In covering sensitive stories, we navigated the ambiguity of the shifting grey zone, guided by interviewees who had often spent decades skating on that political thin ice. This is not possible in Hong Kong, where a gigantic black zone has been imposed overnight on what had been a relatively free society. There is no precedent to draw upon, no experts to consult. The fact that no Hong Kong officials – not even the chief executive, Carrie Lam – had seen the legislation prior to its imposition means there are no sources of authority to provide guidance. There are only warnings. Fear is the key to its implementation. That fear is real and it’s working. In the run-up to the law’s enactment, some prominent political groups shut down voluntarily. Nathan Law, the territory’s youngest lawmaker, who was elected in 2016 and then disqualified on a technicality, announced that he had left Hong Kong. The national security law compels internet security providers to comply with the authorities’ requests for information. Now people I know are erasing themselves from view. Facebook pages and Twitter accounts are disappearing, and my phone, which once buzzed incessantly from notifications from Telegram groups, has fallen silent. Friends are asking to move our communications to more secure platforms. Some are even pleading with their contacts to delete all their WhatsApp conversations. In this digital era when so much of our identity is online, removing your own archive is not just self-censorship, it’s an act of self-effacement. But many Hongkongers now fear they have no choice but to cancel themselves as an act of survival. This law is global in scope, applying to non-residents outside Hong Kong. This means that any discussion of Hong Kong politics – in classrooms, newspapers or parliaments around the world – now involves a corollary discussion of risk, particularly if any participants are inside or from Hong Kong. I wrote a book about the steps taken by China’s Communist party to erase the collective memory of the Tiananmen Square killings of 4 June 1989, and its success in muting discussion of the anniversary inside China. I never imagined that the party would try to control public discourse inside freewheeling, vibrant Hong Kong. The extraterritorial nature of this legislation poses an assault on language and freedom of speech that is global in nature. To ignore it risks entrenching those absences worldwide. •Louisa Lim is the author of The People’s Republic of Amnesia: Tiananmen Revisited and a senior lecturer at the University of Melbourne