Japan's controversial major defense policy shift to obtain an enemy base strike capability underscores that the Asian country has become seriously wary of China's possible use of military force against Taiwan, security experts said.

By reviewing its exclusively defense-oriented postwar policy, Japan would put more emphasis ahead on thwarting China's ambition to bolster its military presence in nearby waters than on guarding against North Korea's missile and nuclear weapons threats.

Japanese Prime Minister Fumio Kishida takes a ride in a tank during his visit to the Ground Self-Defense Force's Asaka base straddling Tokyo and Saitama Prefecture on Nov. 27, 2021. (Kyodo) ==Kyodo

But it is uncertain whether Japan's possession of what the government calls a "counterstrike capability" can work as a deterrent against China, as the concept is not designed to enable Tokyo to boost its defense capabilities to pose a threat to Beijing.

At home, meanwhile, some pundits still claim that gaining the capability would violate Japan's war-renouncing Constitution that only allows the nation to have minimum necessary defense power.

In the National Security Strategy updated Friday by Prime Minister Fumio Kishida's Cabinet, Japan promised to acquire the capability to fire upon and disable enemy missiles before they are launched from foreign territory to deter "armed attacks."

The government's long-term security policy guidelines explained that Japan faces the "most severe and complicated security environment" since World War II, in an apparent allusion to China's rising threat.

Toshiyuki Ito, a professor at Kanazawa Institute of Technology's Toranomon Graduate School, said, "For the public, the government has explained that acquiring a counterstrike capability is to address North Korea's missile activities."

North Korea has test-fired longer-range missiles at an unusually fast pace since the beginning of this year, while worries are lingering that Pyongyang could carry out its seventh and first nuclear test since September 2017.

Substantially, however, the latest move "represents Japan's preparedness for a China-Taiwan conflict," Ito said, with the NSS stressing that the peace and stability of the Taiwan Strait are essential for those of the international community as well.

The revision of the NSS, along with two other key defense documents, came as tensions over the self-ruled democratic island of Taiwan have been mounting between Communist-led China and Japan's close security ally, the United States.

Beijing and Taipei have been governed separately since they split in 1949 as a result of a civil war. China regards Taiwan as a breakaway province to be reunified with the mainland.

Chinese President Xi Jinping, who secured an unprecedented third five-year term as head of the ruling Communist Party in October, has not ruled out the use of force to bring the island under its control, repeatedly describing Taiwan as a "core interest."

After U.S. House of Representatives Speaker Nancy Pelosi, the third-highest-ranking official of the country, made a trip to Taiwan in early August, China conducted large-scale military drills near the island in retaliation.

Some ballistic missiles launched from China fell into Japan's exclusive economic zone, jeopardizing the security of the region.

Ito, a former vice admiral at Japan's Maritime Self-Defense Force, said China and Taiwan are more likely than before to engage in warfare within the "next five years," which almost coincides with the period when Tokyo will be trying to double its defense budget.

Under Japan's new security program, around 43 trillion yen ($315 billion) will be allocated to its defense spending for five years from fiscal 2023, jumping up from 27.5 trillion yen under the existing plan for the five years from fiscal 2019.

Out of the envisioned budgets, about 5 trillion yen will be used to obtain "standoff missiles" capable of being launched from beyond the range of enemy fire.

Ito said Japan's acquisition of a strike capability and expansion of its defense spending would serve as a "bargaining power" to discourage China from exerting its military might against Taiwan "to some extent."

People protest against raising Japan's defense spending in front of a House of Representatives office building in Tokyo on Dec. 16, 2022. (Kyodo) ==Kyodo

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Japan vows to obtain enemy base strike capability to address threats

Nevertheless, Ken Endo, a professor at the University of Tokyo's Graduate Schools for Law and Politics, said it is difficult for Japan to dissuade China from military action by only having conventional weapons such as medium-range missiles.

As a pillar of its counterstrike capability, Japan intends to purchase up to about 500 U.S.-developed Tomahawk cruise missiles by the end of fiscal 2027, a government source said. The weapons would put China's coastal areas within strike range.

Endo, well-versed in international politics, said that even if Japan had 500 Tomahawks, the nation could only create "small craters" on the mainland and "wound some people," adding Tokyo would be unable to "deter" China's offensive intentions.

He also said possessing missiles that can reach an opponent's territory would contradict the pacifist Constitution's stipulation that the "Japanese people forever renounce war as a sovereign right of the nation and the threat or use of force as means of settling international disputes."

In the updated NSS, Japan's government pledged "not to become a military power," saying the country would only launch a counterstrike as a "bare minimum self-defense measure."

Former vice admiral Ito said the possession of a counterstrike capability is categorized as a "natural right of self-defense" and does not mean that Japan will abandon its exclusively self-defense policy, which the nation has stuck to for the past 75 years.

Other analysts have voiced concern about whether Japan could carry out counterstrikes in a manner that would not be seen as a pre-emptive attack, while Japan's opposition bloc has requested Kishida's government to draw a sharp line between the two.

Sayoko Tanaka, a professor of international law at Hosei University, said it is "hard and inappropriate" to show clear criteria in advance to judge when Japan would invoke the right to self-defense, but the government should "achieve accountability."

To exert an enemy base strike capability properly, Japan should get ready to "precisely grasp the situation of opponents' preparations for an armed attack and its launch," Tanaka added.

Japanese Prime Minister Fumio Kishida speaks at a government-ruling bloc meeting on Japan's defense capabilities in Tokyo on Dec. 16, 2022. (Kyodo)