TOKYO -- A conflict in the Taiwan Strait would present one of the biggest challenges to Japan's security, a new defense white paper shows, as Tokyo delves into unprecedented detail on how it plans to protect the country's territory in such a scenario.
Japan must "pay close attention" to the Taiwan Strait "with a sense of crisis more than ever before," the document published Tuesday said.
The Defense Ministry cited the importance of cross-strait stability in its annual report for the first time, signaling a growing sense of urgency from the 2020 white paper, which said "attention needs to be paid to trends" regarding Chinese and Taiwanese forces. China has refused to renounce the use of force to reunify self-ruled Taiwan with the mainland.
Should an armed clash break out in the strait, Japan likely would need to protect U.S. warships carrying Japanese evacuees from the region and defend American bases against missile attacks under the principle of collective self-defense. Members of the government and ruling Liberal Democratic Party increasingly see a crisis involving Taiwan as a crisis for Japan.
Fighting could spread easily to Japan's remote Nansei Islands, which include the Senkaku Islands -- located just 170 km from Taiwan and claimed by China as the Diaoyu -- as well as Yonaguni Island. Japan and the U.S. would jointly defend these islands should they become a war zone.
The greater focus on island defense reflects the region's changing geopolitics. Japan's top security concern after World War II was a potential invasion by the Soviet Union. Tokyo's priority shifted to peacekeeping operations and disaster relief by the Self-Defense Forces following the Cold War, then to North Korea's missile threat in the 2010s.
But the threat posed by Beijing also loomed heavy through the years. Tokyo repeatedly expresses concern over Chinese activities near the Senkakus, but the 2021 white paper stands out in highlighting Japan's detailed plan for protecting its territory.
Island defense is a key component of this plan. The white paper cited Japan's intent to extend the range of the Type 12 surface-to-ship missiles used by the Ground SDF, so it can shoot down incoming threats and deter strikes against Japan's remote islands.
The document noted Japan's plans for new Aegis-equipped warships, to replace the land-based Aegis Ashore missile shield whose deployment was canceled last year. Aegis Ashore had been intended as a defense against North Korean missiles, but a ship-based system also can be used to defend the Nansei Islands.
The new white paper also outlines Japan's response to "gray zone" situations, or conflicts that fall short of war. They could include China's Coast Guard landing on the Senkakus, for example.
"Recent years have seen a continued tendency towards the prolongation of 'gray zone' situations that are associated with territories, sovereignty and economic interests, and such situations may increase and expand in the future," the white paper said. The document also devoted space to the importance of joint training by the SDF and police to deal with armed foreign agents.
The white paper for the first time dedicated a section to U.S.-China relations as well, warning of their impact on Japan. It predicted greater rivalry between Washington and Beijing on artificial intelligence and other cutting-edge technologies.
China has expanded its fighter jet and missile fleets rapidly since 2000, making it a dominant military power in East Asia. Beijing's strategy is to keep the U.S. from approaching nearby waters through a large-scale deployment of anti-ship missiles and other arms.
China strongly opposes Washington's stance that the U.S. obligation to protect Japan under their bilateral security treaty applies to the Senkakus, the white paper said, in an unusual remark tying the island to the U.S.-China rivalry.
The Senkakus received their own section as well. Chinese activities around the islands, like repeated coast guard incursions into the chain's surrounding waters, "are, fundamentally, a violation of international law," the document said. Past white papers slammed such actions but did not comment on their legality.
China's Coast Guard Law, which took effect in February and gave the agency quasi-military status, "includes problematic provisions in terms of their inconsistency with international law," the document said. The law has prompted concerns that actions by the Chinese Coast Guard around the Senkakus could lead to a gray zone situation or full-fledged crisis.
In terms of Japan's defense budget, the white paper said the country had the lowest figure as a percentage of gross domestic product compared with other advanced economies -- 0.94% in fiscal 2020.
But the budget increased spending for a ninth straight year in fiscal 2021, and is expected to continue growing in fiscal 2022. Defense Minister Nobuo Kishi has signaled that Japan is ready to scrap a longtime ceiling of 1% of GDP on annual defense spending.