“Japan’s submarine fleet is particularly worrisome to China because of Beijing’s traditional weakness in anti-submarine warfare (ASW). China has not practiced ASW in wartime and has been institutionally deficient in both skills and assets. Japan, on the other hand, has operated submarines for many decades. Japanese submarine crews are reportedly well trained, on par with their American counterparts.”
“Five Japanese Weapons of War China Should Fear“, The National Interest, 6/14/14.