January 30, 2018

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. 


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.


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
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. 


PUNTER said...

Even Chinese media say the sub was type 093B by analyzing the photo provided by Japanese defense ministry.



and this is an old article about 093B with photo (2016)

PUNTER said...

In your hypothetical theory, Chinese Navy used the sub for a "demonstration" purpose? You really think so?

Peter Coates said...


I have several theories - described in the article.



PUNTER said...


You wrote, Jan 11 the sub surfaced.

But, according to Japan Defense Ministry, the sub entered Senkaku's contiguous water on Jan 11 a.m., exited on Jan 11 p.m.(submerged), surfaced in East China Sea on Jan 12 p.m.

Tri-ring said...

There was an interesting speculative article on Jan 31st Nikkei Newspaper about this incident.
It was on the second page to those who are interested.

Peter Coates said...

Hi Tri-ring

Thanks for the tip. But a string of the article as it appears in the online Nikkei Newspaper (rather than a hard copy reference) would by useful.



PUNTER said...

A former JMSDF officer Yoji Koda (香田洋二 ) gave his comment to Japanese newspaper Yomiuri Shinbun, " (the fact that the sub was continuously monitored and chased by JMSDF) gave strong shock to Chinese Navy".
A high ranking official of Japanese Defense Ministry said, "it was fruitful that Japan was able to get Shang-class sub's data".


Peter Coates said...


I have altered the wording of the Submarine Matter's article more in the direction that it was a Chinese Navy miscalculation. I wonder if the Chinese Captain was sacked?



PUNTER said...

you are welcome.

some people say, they see variable depth sonar in the sub's photo taken by JMSDF. though, I don't know what it means.

Josh said...


I had assumed this was a training mission due to the presence of the Type 54. Its not clear to me why the PLAN would pair a nuke boat with a surface ship unless they assumed it would be detected anyway. I don't see why they could possibly be surprised that a PLAN ship attracted platforms that also would have acoustic sensors to detect the boat - by pairing the two, they basically handed initial detection and localization to the JMSDF.

It also seems perfectly likely a USN boat was in play as well, given how few nukes the PLAN has and how infrequently they deploy. Assuming there was even one USN boat inside the first island chain, it probably would have been tasked to follow the deployment.

It seems rather unlikely that the PLAN learned more than the JMSDF did. This comes back to the quandary I mentioned concerning the PLAN having foreign navies in own back yard.


twitter: @squid_jigger

Peter Coates said...

Very true Josh

Chinese intentions remain murky and unresolvable as no Chinese Admiral or, at least senior Captain, has said what the 093 planned to achieve.

So we are reduced to logic. Certainly deploying the Chinese frigate acted as a tracker buoy highlighting the 093's position.

So then I think the frigate and 093 were performing a political FONOPs purpose. That is claiming China had as much right to be in the Senkakus area as Japan.

Perhaps, also, the frigatewas protecting the 093 from US or Japanese surface ship interference. This may have come in the form of constant high volume active sonar beeps or even mini-grenade-depth-charges dropped over the side.



PUNTER said...

If the sub's purpose was any kind of demonstration (FONOP or whatever), that means, Chinese Navy expected that the sub would be detected by Japan or US. with cost of giving the sub's data of acoustics, speed, depth. This demonstration theory seems highly debatable, especially in this case, many people believe the sub was new type 093B, not old 093.