For over a decade, a handful of Hong Kong bookshops served as a rare window for mainland Chinese visitors to access works on topics such as the Tiananmen Square crackdown, the Uyghur internment camps, and critical histories of the Communist Party. These stores, often located in busy shopping districts, attracted curious tourists and intellectuals from across the border who could not find such titles in their own country.

Now, several of these shops have closed or announced they are closing permanently. Owners cite a combination of falling sales, increased regulatory scrutiny, and a climate of fear that has spread since the passage of the Hong Kong national security law. The law, which bans acts of secession, subversion, terrorism, and collusion with foreign forces, has been used to target activists, media outlets, and even book distributors.

The closures represent a significant shift from the era when Hong Kong was widely seen as a bastion of free expression within China. Some shop owners who spoke to the BBC on condition of anonymity said they had faced pressure from authorities to remove certain titles or risk losing their licenses. Others said the risk simply outweighed the reward as customers became more cautious.

One Hong Kong-based publisher, who declined to be named, said: "We used to see mainlanders walk in and spend hours reading. Now they are afraid to even pick up a book with a cover that looks suspicious. The whole atmosphere has changed."

Supporters of the national security law argue that it is necessary to protect national security and that any bookshop found distributing material considered subversive must comply with the law. They contend that the rule of law is being enforced equally, and that businesses that choose to close are making voluntary commercial decisions.

According to data from local book trade associations, sales of books on sensitive political topics have declined by more than 60% since 2020. Meanwhile, self-censorship has become widespread. Many bookstores now refuse to stock controversial titles, even those that are legally permitted, to avoid drawing attention from authorities.

The trend has alarmed human rights groups and free speech advocates, who see it as evidence that Beijing is systematically eliminating spaces for dissent. Amnesty International said the closures "deal a severe blow to intellectual freedom across the region."

For mainland Chinese who once made day trips to Hong Kong specifically to purchase banned books, the loss is personal. One university student from Shenzhen told the BBC: "I don't agree with everything in those books, but I want the right to know different viewpoints. Now I don't even know where to go."

As the doors close on these shops, Hong Kong's role as a hub of diverse ideas appears to be fading. Whether any alternative channels will emerge to fill the gap remains uncertain.