For years, China has been beefing up its armed forces and expanding its military operations beyond its borders.

But there are too many unknowns about the Chinese forces. This lack of transparency in the country’s rapidly growing military presence is amplifying anxiety among countries in neighboring regions and the rest of the world.

China plans to increase military spending by 8.1 percent in 2018 from the previous year to more than 18 trillion yen ($169.17 billion), according to the government’s draft defense budget submitted to the National People’s Congress session, which started March 5.

The budget is more than three times higher than Japan’s defense expenditures and the second largest in the world.

But the spending plan only contains the total amount and some policy slogans such as “providing powerful support to help realize the dream of a strong military.” It offers no breakdown of the spending.

The statement by no means qualifies as a sufficiently informative description of the defense budget any major power should offer to the world nor as a responsible accounting owed to Chinese taxpayers.

The defense white paper drafted by the Chinese Ministry of National Defense doesn't reveal any substantial information about the country’s military capabilities, such as weapons used by its army, navy and air force.

The document was still meaningful since it provided some clues as to the Chinese military’s thinking. But no new version has been published since 2015.

The consensus view among military experts in the world is that many military outlays have been left out of China’s defense budgets, including spending to develop new weapons.

Last year, the Chinese navy started operating a base in Djibouti, a country in northeastern Africa.

China has also acquired the rights to use ports in South Asia, raising concerns that the ports will be turned into military facilities.

In the South China Sea, China is building military bases on reclaimed land around reefs in disputed areas.

There have also been rumors that China is planning to build a nuclear-powered aircraft carrier.

The latest report by the International Institute for Strategic Studies in London warns that the U.S. air space supremacy will be threatened by China’s future deployments of stealth fighters and new air-to-air missiles.

In addition to bolstering its nuclear arsenal, China is also enhancing its military capabilities for cyber and space warfare.

China has never offered a convincing explanation about its rapid military buildup to the international community. It is irresponsible and dangerous behavior.

Chinese President Xi Jinping seems to have taken control of the country’s entire armed forces by pushing through a reform of the military organization.

The Chinese military, however, has made some baffling moves.

Immediately before Xi’s visit to India in 2014, for example, Chinese troops crossed the Line of Actual Control that separates Indian- and Chinese-controlled territory in a disputed border region.

In January, amid an improvement of the relationship between Tokyo and Beijing, a Chinese submarine approached the Senkaku Islands, a group of islets in the East China Sea that are controlled by Japan but also claimed by China.

Are these China's diplomatic tactics drawing on its bulging military muscle? The dark cloud of secrecy surrounding them is also ominous.

In its new National Defense Strategy, the U.S. Defense Department warns that China is seeking “Indo-Pacific regional hegemony.”

But any shift in the U.S. defense policy toward a hard-line stance to China could prompt Beijing to step up its military buildup, triggering a vicious arms race.

To avoid this trap, countries concerned should work together to pressure China to take steps toward injecting more transparency into its military spending and operations.

Serious efforts to turn the trend, such as talks for nuclear nonproliferation and arms reductions as well as military exchanges to build mutual trust, should be made to prevent an accelerating arms race.

--The Asahi Shimbun, March 6