The military balance between China and Taiwan is "rapidly tilting to China's favor," Japan said in its annual defense report released Friday, amid tensions over the self-ruled island that Beijing considers its territory.

The Defense Ministry's 2023 white paper, received by the Cabinet of Prime Minister Fumio Kishida the same day, said there is increasing global concern about China's intensifying "coercive military activities" in the skies and waters surrounding Taiwan.

Shiyu, or Lion Islet, part of Kinmen County, one of Taiwan's offshore islands, is seen in front of the Chinese city of Xiamen, China, on April 20, 2018 in Kinmen, Taiwan. (Getty/Kyodo)

In last year's report, Tokyo said that the military balance between Beijing and Taipei was "tilting to China's favor, and the gap appears to be growing year by year."

The white paper was released amid an intensifying rivalry between the United States and China over issues such as Beijing's provocative military activities near Taiwan.

Taiwan and China have been governed separately since 1949 due to a civil war. Communist-ruled China regards the democratic island as a breakaway province to be reunified with the mainland, by force if necessary.

Defense Minister Yasukazu Hamada holds up a copy of Japan's annual defense report in Tokyo on July 28, 2023. (Kyodo)

A contingency involving Taiwan is a particularly concerning prospect for Japan, a U.S. ally, given the proximity of its southwestern islands, including the Tokyo-controlled, Beijing-claimed Senkaku Islands in the East China Sea.

Defense Minister Yasukazu Hamada told a press conference the defense paper contains Japan's "candid views" on the Taiwan situation, and underscores the government's unchanged stance that problems "should be always resolved through dialogue."

Days after a visit to Taiwan last August by then U.S. House of Representatives Speaker Nancy Pelosi, China staged large-scale military exercises around Taiwan that included the firing of ballistic missiles, five of which fell into Japan's exclusive economic zone.

The latest report says that during the exercises, the Chinese military may have simulated operations for "invading Taiwan," such as anti-ground and anti-ship attack drills, as well as those for gaining air and naval supremacy.

"The fact that China is capable of carrying out such activities shows that the situation is working to China's advantage," a Defense Ministry official told reporters.

The paper also cited a "significant increase" in the number of Chinese aircraft entering Taiwan's airspace, rising from 972 in 2021 to 1,733 in 2022, as another sign of the shifting military balance.

The report described China as "a matter of serious concern" for the global community, saying the country presents the "greatest strategic challenge," to which Japan should respond through "cooperation and collaboration" with the United States, as well as other "like-minded countries."

Describing China in such terms, first seen in the National Security Strategy updated by Tokyo in December last year to address the increasingly severe regional security environment, was considerably more severe compared to last year's report, which simply referred to Beijing as "a matter of grave security concern."

Also in the government's long-term security policy guidelines, Kishida's administration vowed to obtain counterstrike capabilities to reach targets in enemy territory, a significant shift from Japan's exclusively defense-oriented policy under its war-renouncing Constitution.

The white paper also said China may push forward its plan to build "world-class forces by the mid-21st Century," while airing "grave concern" regarding increasingly close China-Russia military ties.

The two nations' "repeated joint bomber flights and joint navigations of vessels" are "clearly intended for demonstration of force against Japan," it said.

China lodged a protest with Japan over the white paper, with Foreign Ministry spokeswoman Mao Ning saying at a press conference in Beijing it "gravely interferes in China's internal affairs" and "smears the country's normal defense development."

Calling the cross-strait military balance "a false proposition," Mao said the white paper "deliberately hypes up the China threat narrative and creates tension in the region."

She also defended joint patrols conducted by China and Russia, saying they are "in line with international law and customary international practice."

Regarding Russia, the report assessed its national strength will likely decline "in the medium- and long-term, because of significant casualties of conventional forces" caused by its ongoing war in Ukraine that began in February last year.

Meanwhile, the defense document warned Moscow is likely to further rely on its nuclear capabilities as a deterrence.

As for North Korea, the paper said the reclusive country has "forcibly conducted" ballistic missile launches "with an unprecedented frequency" since the start of 2022.

Pyongyang's nuclear and missile programs "pose an even more grave and imminent threat to Japan's security than ever before," the defense document added.