Prime Minister Sanae Takaichi shakes hands with Chinese President Xi Jinping ahead of their October 31 Japan-China summit meeting in Gyeongju, South Korea. (©Kyodo)
"Cognitive warfare" refers to the use of disinformation to shape perceptions and influence behavior. It resembles the spread of a pathogenic virus, with even unsuspecting individuals contributing to its transmission.
A post alleging that "Prime Minister Sanae Takaichi's grandfather was a major in the Japanese military that invaded China," written in simplified Chinese used on the mainland, began circulating across social media in China and Taiwan roughly two weeks after her parliamentary remarks on a Taiwan contingency last November.
What began in China and disseminated primarily in Taiwan is now emerging as a growing threat to Japan.
A Manufactured Narrative
Multiple versions of the post are in circulation online, with Takaichi's grandfather's name alternately given as "Hayao" or "Toshihiko."
Each features an image purportedly depicting an Imperial Japanese Army officer poised to strike a kneeling Chinese man. The post identifies the officer as the Prime Minister's grandfather and urges "the overthrow of the resurgence of Japanese militarism."
A private organization, the Taiwan FactCheck Center, determined that Takaichi's grandfather's real name was Masayoshi and classified the post as misinformation. "The origin is clearly from China," Hsu Yun-kai of the center said.
Pro-China commentators in Taiwan also contributed to amplifying the false claim. Chiu Yi, a former Kuomintang legislator, appearing on a December debate program on TVBS, a major Taiwanese network, said: "Toshihiko Takaichi, a former Army major, was part of the Japanese forces that carried out the Nanjing Massacre. He is the grandfather of Takaichi, who is enshrined at Yasukuni Shrine."
False claims also circulated in November alleging that the Prime Minister had received precious metals as a bribe in 2023 from Frank Hsieh, then head of Taiwan's representative office in Japan.
An email attributed to an associate of the Prime Minister was cited as evidence. Yet the fact-checking center found the wording unnatural and concluded it was "Japanese written by a Chinese speaker."
Engineering Division and Chaos
"Anti-US sentiment, which fuels distrust of Washington, has long circulated in Taiwan, but false information designed to stoke anti-Japan sentiment is now growing rapidly," said Shen Boyang, a Democratic Progressive Party legislator and cognitive warfare researcher.
According to Shen, China's campaign serves clear political and military ends. Over the long term, it seeks to force Taiwan to accept the Chinese takeover of the island while discouraging intervention by Japan and the United States. In the medium term, it aims to interfere in elections, and in the short term, to sow social chaos and division.
In the Kuomintang chairperson election in October 2025, Cheng Li-wen, who is known for her pro-China stance, was elected. Taiwanese national security officials described the outcome as "the first instance of China fully intervening in an internal election of a Taiwanese political party."
They assess that a military-linked intelligence unit spent hundreds of millions of Taiwan dollars to disseminate fake AI-generated videos.
A War Without Borders
Zeng Yishuo, an associate researcher at the Institute for National Defense and Security Research, a think tank affiliated with Taiwan's Ministry of National Defense, says China drew lessons from the 2016 US presidential election, widely seen as a successful case of Russian interference, and subsequently intensified pressure on Taiwan.
In January 2026, Taiwan's National Security Bureau warned that Chinese public and private influence units, often referred to as "cyber armies," are operating across more than 180 social media platforms worldwide, including in Japan.
Cognitive warfare spreads quietly, like a virus, eroding societies from within. Building resilience against it has become an urgent priority.
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Author: Yoshiaki Nishimi, The Sankei Shimbun
(Read this article in Japanese)
