When all of you will realise that waves used for underwater sonars are the same in every country around the world and it comes from pretty simple physics. It's more about software, hardware and skill, not frequencies. All that Chinese could gather was info that JMSDF uses the same frequencies as them for ASW... like they didn't know already.
Not really. Like radars, sonars comes in at an enormous range from long to short, and wave forms change with purpose --- lower for longer ranges, high frequency for shorter range but higher rate of track. Sound forms have infinite variations, and are constantly affected by water temperature and salinity, changing the sound itself. That can be used to identify the sonar and what vessel it is, sort of like every sonar has their signature, and which can also be used to figure out its intent. Some of the ASW equipment maybe newer than others, stuff are constantly updated, new ships are released, how warming waters are affecting all these, this form of information always needs to be updated in a database.
If they have not recorded the ASW sounds before, or if the JSDMF isn't dumb enough to ping the submarine, the sounds of the surface vessels themselves are also convenient. Sounds of vessels may differ even from members within the same class, and if the same ship gets refitted or upgraded. Another convenient information would be the water temperature and salinity of the surrounding area, the thermal layers, wave propagation effects near the surface, just above and below the thermal layers and so on. How far you can passively pick up the surface vessels might be convenient too, as well as the ability to differentiate the the sounds of the allied vessel (conveniently supplied with the Type 054A) against non allied (JS destroyers) after water propagation effects would also be welcome.
This won't be the end of it though, as you would want to know the water conditions every season.