In the East China Sea, China has all of the advantages against Japan. Since China has entered mass production of J-20 stealth fighters, China will have air superiority. By controlling the airspace, China can bring all of its anti-submarine assets into play.
China has anti-submarine warfare capability.
1. China has a lot of nuclear and diesel-electric attack submarines. Japan is outgunned in quantity and quality.
2. China has Type 054A frigates and Type 056 light-frigates that have towed-array VDS (ie. variable depth sonar) to detect submarines.
3. China has a Sino-SOSUS network in the East China Sea.
4. China has Z-9C helicopters with anti-submarine warfare equipment that can fly from Type 052C/052D destroyers, Type 054A frigates, or Type 056 light frigates.
"Type 054A features a helipad and hangar for a medium sized helicopter."
5. China's Y-8Q is equivalent to the American Poseidon P-3C sub-hunter airplane.
In conclusion, Japanese Soryu submarines are not likely to survive for very long.
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Additionally, a Chinese Yuan with AIP should be far superior to a Japanese Soryu. The Chinese Yuan has flank sonar arrays. I believe the sonar arrays use interferometry. Also, China builds the world's fastest supercomputers. Since supercomputers are use in digital signal processing, China should have the edge in identifying a Japanese submarine.
The Chinese Type 095 submarine crew will gain valuable experience training on the digital simulator. Since the Chinese government is flush with a massive trade surplus, we expect Chinese submarine crews to be better-trained than Japanese crews.
Yuan submarine "low-frequency passive flank array"
The following is an excerpt of the full article regarding China's Yuan submarine at USNI News.
Essay: Inside the Design of China’s Yuan-class Submarine - USNI News
