Taiwan President Tsai Ing-wen made a formal apology to the aboriginal people of the island earlier this week.

“Unless we deny that we are a country of justice, we must face up to this history,” Ms. Tsai said. “We must tell the truth. And then, most importantly, the government must genuinely reflect on this past.”

According to Ms. Tsai’s statement, made at a ceremony in the presidential office attended by representatives of Taiwan’s aboriginal groups, her apology was just the first step in a process to make amends for centuries of “pain and mistreatment.”

But Ms. Tsai’s apology could be seen as more than a gesture meant to heal old wounds in Taiwan. The language she used also presents a direct challenge to mainland mythologizing about China’s past and present territorial claims.

By apologizing for colonialism by Han Chinese toward the aboriginal people on Taiwan, Ms. Tsai contradicts a long cherished trope of Chinese exceptionalism: that China has never invaded or colonized another people.

While many of China’s neighbors — and a few of her own indigenous groups might disagree — the idea of China’s eternal peace with all groups within and without its borders is considered a near universal truth by many Chinese citizens on the mainland. Ms. Tsai’s apology cuts at the very heart of this exceptionalism.

Even the act of apologizing is at odds with prevailing trends in Beijing. At the same time Ms. Tsai is calling for Taiwan to reflect on its past, Party officials on the mainland are declaring war on “historical nihilism.” Party journals this summer have repeatedly accused scholars in and out of China of dredging up (or fabricating) past atrocities as a way of undermining the Party and the government’s legitimacy.

The idea of a leader in Beijing apologizing for the past — never mind an apology for past mistreatment of non-Han peoples — exists on the same plane of probability as Donald Trump putting on work boots and Dickies to build transgender-friendly bathrooms for Mexican Muslims.

Finally, as was first mentioned on the View from Taiwan Blog maintained by Michael Turton, Ms. Tsai’s apology changes Taiwan’s relationship with the mainland. Mainland narratives — whether those of the Chinese Communist Party or the Nationalist Party who fled the mainland to Taiwan in 1949 — assumed the island to be an inherent part of a larger Chinese nation. By establishing Taiwan as a colonial project by the Han Chinese, Ms. Tsai has deftly shifted focus to the island’s own historical development outside of Chinese nationalist narratives.

Beijing continues to pressure Ms. Tsai’s government not to take any steps which might jeopardize the “status quo.” Earlier this year, one of China’s state newspapers questioned Ms. Tsai’s emotional stability as an unmarried woman. More recently, a rap video distributed online with the blessing of the Chinese Communist Party referred to Ms. Tsai in English as a “f——-g b—-h.”

But with her statements this week, it appears that Taiwan’s president may rise above the angry rhetoric and find other ways to rankle her counterparts on the mainland.