This article analyzes Masao Shimojo’s detailed examination of why “a Taiwan contingency is a Japan contingency,” a concept originally emphasized by former Prime Minister Shinzo Abe. Following Prime Minister Sanae Takaichi’s Diet statement that a Taiwan crisis involving the use of force could constitute a “survival-threatening crisis,” China launched immediate diplomatic pressure through travel warnings, study-abroad restrictions, and economic intimidation. Shimojo explains how China views Taiwan and the Senkaku Islands as inseparable and how Beijing models its strategy on South Korea’s seizure of Takeshima. The essay also highlights the diplomatic missteps of Japan’s former DPJ administration and the need for Japan to strengthen strategic information dissemination to defend sovereignty against China’s ongoing historical and territorial warfare.
Taiwan Contingency Means a Japan Contingency
by Masao Shimojo

Since former Prime Minister Shinzo Abe stated in a December 2021 lecture after stepping down from office that “a contingency in Taiwan is a contingency for Japan, and therefore a contingency for the Japan-U.S. alliance,” the phrase “a Taiwan contingency is a Japan contingency” has become indispensable when discussing Japan’s security policy.
This concept took on concrete reality during the House of Representatives Budget Committee session on November 7 this year.
Katsuya Okada of the Constitutional Democratic Party asked, based on a hypothetical scenario: “In last year’s LDP presidential race, you said that if China were to blockade Taiwan by sea, ‘it might constitute a survival-threatening crisis.’ Under what circumstances do you believe this would occur?”
Prime Minister Sanae Takaichi responded: “If a Taiwan contingency involves warships and includes the use of force, then no matter how one looks at it, it is a case that could indeed constitute a survival-threatening crisis.”
This exchange was the starting point.

The Chinese government demanded that Prime Minister Takaichi retract her statement.
China displayed elements of so-called “wolf warrior diplomacy,” calling for Chinese citizens to refrain from traveling to Japan, urging caution regarding study abroad in Japan, and declaring that even if Japanese seafood were exported to China, there would be “no market” for it.
This was likely because Prime Minister Takaichi’s answer ran counter to the stance on the Taiwan issue expressed in the “Report to the 20th National Congress of the CCP” in October 2022.
The report stated that China would “fully and accurately advance the practice of ‘one country, two systems,’” that it “firmly opposes separatist activities aimed at ‘Taiwan independence,’” and that it “firmly opposes interference by external forces.”
It also declared that “resolving the Taiwan issue and achieving the complete reunification of the motherland is the unwavering historic mission of the Party.”
It described this as an “inevitable requirement” for achieving “the great rejuvenation of the Chinese nation,” adding that China “will never commit to renouncing the use of force” in resolving the Taiwan issue.

China, envisioning the military unification of Taiwan, likely interpreted Prime Minister Takaichi’s remarks as meaning that Japan would exercise the right of collective self-defense and become involved if a Taiwan contingency were deemed a survival-threatening crisis.
For the Chinese government, which regards Taiwan as an “inalienable part of the territory of the People’s Republic of China,” Takaichi’s statement was tantamount to interference by an external force obstructing “the great rejuvenation of the Chinese nation.”

The Senkakus as “Affiliated Islands”

The Japanese government adopted an ambiguous stance toward Taiwan in the 1972 “Japan-China Joint Communiqué,” stating that it “fully understands and respects the position of the Government of the People’s Republic of China that Taiwan is an inalienable part of the territory of the People’s Republic of China.”
Prime Minister Takaichi’s remarks went a step further, likely giving China the impression that Japan had crossed a red line.
Thus, China labeled Takaichi’s answer “interference in internal affairs” and demanded a retraction—something difficult to comply with.
If Prime Minister Takaichi retracts her statement, it would play into China’s designs; if she refuses, China will continue harassment verging on intimidation.
This outcome is undesirable for both Japan and China.

In February 1992, the Chinese government enacted the “Territorial Waters Law,” and Article 2 defined the territory of the PRC as including “Taiwan and its affiliated islands (Diaoyu Islands, Penghu Islands, Dongsha Islands, Xisha Islands, Zhongsha Islands, Nansha Islands).”
Since then, China has regarded Japan’s Senkaku Islands (called Diaoyu by China) as “affiliated islands” of Taiwan and has sought their possession.
This is precisely why “a Taiwan contingency is a Japan contingency.”

Modeling the Takeover of Takeshima

On September 7, 2010, a Chinese fishing boat deliberately rammed a Japanese patrol vessel near the Senkaku Islands.
Katsuya Okada was serving as foreign minister in the Democratic Party of Japan (DPJ) government at the time.
Diplomacy under the DPJ administration not only undermined Japan’s position regarding the Senkakus but also created openings for China’s expansion into the Spratly Islands.
The DPJ also committed errors regarding Takeshima.
A DPJ lawmaker close to Prime Minister Naoto Kan reportedly stated in the South Korean National Assembly that “Takeshima belongs to South Korea,” and as foreign minister Okada repeatedly refused to utter the phrase “South Korea is illegally occupying Takeshima” when questioned by LDP lawmakers.

China, seeking to seize the Senkakus, is using South Korea’s takeover of Takeshima as a model.
On November 17 this year, Foreign Ministry spokesperson Mao Ning responded to questions at a regular press conference about Takeshima and Japan’s “Territory and Sovereignty Exhibition Hall.”
South Korea’s Yonhap News (online edition) and other outlets reported that she said Japan’s “malicious actions” are provoking “vigilance, dissatisfaction, and protests from neighboring countries.”
In South Korea, it was interpreted as China indirectly criticizing Japan by using the Takeshima issue and aligning with the South Korean position.

However, when the Japanese government opened the “Territory and Sovereignty Exhibition Hall,” its emphasis regarding the Senkaku and Takeshima issues was on “raising public awareness and disseminating information internationally.”
Thus, Japan’s claims are being presented, but the mistaken historical perceptions of China and South Korea are not being addressed.

Roughly a decade ago, I served as a member of a committee on information dissemination regarding the Takeshima issue.
I argued that a research institution was needed to conduct such dissemination, but my opinion was removed from the final report.
Therefore I proposed to the Japan Institute of International Affairs the idea of webinars on the Senkaku and Takeshima issues, and the naming of the Sea of Japan.
Used strategically, these could serve as a deterrent against China and South Korea.
(Emeritus Professor, Takushoku University; Visiting Professor, University of Shimane)