Japan Fears South Korean Attack?

After reading this article in the Chosun Ilbo you would think the Japanese are concerned a South Korean attack on their islands:

Japan appears worried about Korea’s defense reform plans including large-scale troop cuts and increases in spending on cutting-edge technology and has asked Korea’s Defense Ministry for details of the plan, according to a source.

“The Japanese Defense Department has, on a few occasions, informally requested explanation of the background and contents of the National Defense Reform Act,” a government source said. Tokyo appears to worry that the new-model submarines and Aegis combat vessels to be acquired under the plan could be a threat to the island country.

I think the Japanese are more concerned about South Korea not being able to defend themselves from North Korean attack than fearing an invasion of Tsushima island. The less capable the South Koreans are of defending the peninsula more unstable the entire region becomes if the North Koreans look to exploit it.

I would think the Japanese have every reason to want to obtain as much information as possible about the ROK military transformation in regards to their own national security.