China's January 11, 2018, Type 093 Submarine Incursion A SIGINT Probe?

Comments here by "PUNTER" and others, has prompted me to revisit the January 11. 2018 incursion of a (probably) Chinese Type 093 SSN into the Japanese claimed “Senkaku” islands-sea area. The incursion appears to be a:

-  Chinese politico-strategic demonstration that China also claims those islands-waters, 

-  a reconnaissance-intelligence exercise to test the efficiency of Japanese and probably America

   ASW fixed and mobile sensors, OR

-  a miscalculation by China's Navy (PLA-N) that its 093 could carry out a mission undetected by
   Japanese (and possibly US) sensors.

The Chinese exercise would allow China to “trace” or “track” predictable responses by Japan’s intelligence agencies and politico-military chain of command the exercise could yield some decoded SIGINT benefits and undecoded traffic analysis analytical benefits. 

The incursion by the 093 and a Chinese Type 054/054A Frigate was beneficial to Chinese electronic interception as it attracted Japanese MPAs and surface craft. If a Japanese submarine was also sent then Chinese tracking of it would be an even greater intelligence prize. 

BACKGROUND

Two Type 093s, were built in the 2000s, and at least 2 or 3 more improved (could be called Type 093As) were commissioned in 2016. The Type 093A reputedly have vertical launch YJ-18 supersonic anti-ship cruise missiles and may be as stealthy as unimproved US Los Angeles class SSN-688s) and  much quieter than China’s first and noisy Type 091 SSNs.

Side view of a Chinese Type 093. Note old fashioned (maybe 1990-2009 design) cruciform rudder, instead of modern x-plane rudder. See much larger.

---

The January 11, 2018, Type 093 forced to surface or it surfaced to show the Chinese flag. Note that the cruciform rudder may indicate that the Type 093 might have only have been "old style" "unimproved?"  (Mark. 1(?)) build in the 2000s (Photo via Kyodo News).

---

For security and deception China has variously called the Type 093 (or allowed it to be called) "unimproved [2000s build]" "improved [2016 build], plain 093, 093A, 093B and 093G. "Shang" is a NATO reporting name. What the 5 Type 093s are called seems to rely more on what the non-Chinese observers decide to call it rather than usually secret Chinese designations.

FURTHER THEORIES ON THE MISSION

The Type 093 perhaps entered the Miyako-jima (island) part of the Senkakus:

-  without an expectation of detection, or

-  to see how close it could get to Japan’s seafloor SOSUS array or Japan's Integrated Undersea

   Surveillance System (IUSS) (here's the US IUSS) which is SOSUS + many additional sensor 
   platforms). The map below may be the US-Japanese SOSUS-IUSS.

This method of gauging the sensitivity of Japanese and US sensors is very useful to China. Also ease or difficulty of detection would assist China in indicating how many additional stealth improvements or efforts with existing stealth features are required.

If, it is an old Type 093 then China may wish to deceive Japan-US into conclusions that the submarine “could be too easy to detect”

I would conclude “there is not enough information to back up [the easy to detect] theory”.

Better to be a bit pessimistic in intelligence assessments than too optimistic.

“Map 4. The US ‘Fish Hook’ Undersea Defense Line” in Desmond Ball and Richard Tanter, The Tools of Owatatsumi Japan’s Ocean Surveillance and Coastal Defence Capabilities (2015, ANU Press) page 54. The map may depict past or current locations of the eastern Asia - inner western Pacific SOSUS-IUSS seafloor array. 

---

Pete