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Japan's release of video of S. Korean radar lock-on incident inconclusive as proof

The South Korean destroyer that Japan claims aimed its fire-control radar at a Japanese Maritime Self-Defense Force P-1 patrol plane on Dec. 20, 2018. (Photo provided by the Ministry of Defense)

TOKYO -- The Defense Ministry's failure to disclose data on radar waves and other key information when it released a video of an alleged fire-control radar lock-on incident by a South Korean destroyer on a Japanese patrol plane over the Sea of Japan highlights the limits to disclosing sensitive defense information.

The video dismissed South Korea's claim that the Maritime Self-Defense Force (MSDF) plane was flying in a dangerous way above the destroyer. However, since the video is not accompanied by data such as that on the frequency of radar waves, experts say the video is insufficient as evidence that the MSDF P-1 patrol plane was targeted several times by the South Korean ship's fire-control radar on Dec. 20.

In this May 14, 2017 file photo, a Maritime Self-Defense Force P-1 patrol plane flies over the city of Chofu in western Tokyo. (Mainichi/Yosei Kozano)

The issue will inevitably worsen bilateral relations that have already been chilled by South Korean Supreme Court rulings that ordered Japanese companies to compensate former South Korean war-time forced laborers.

The 13-minute-and-seven-second video starts with a scene of the P-1 patrol aircraft approaching a South Korean navy destroyer and a South Korean maritime police security and rescue ship that lined side-by-side.

The video shows two small boats that had been lowered into the sea from the security and rescue ship approaching a fishing boat believed to be North Korean. Crewmembers of the South Korean vessels were apparently trying to rescue those on the fishing boat.

The sea around the area was calm with about 1-meter-high waves and a visibility of some 20 kilometers.

Some South Korean media outlets pointed to the possibility that the South Korean destroyer used radar to swiftly look for the fishing boat. However, Defense Minister Takeshi Iwaya has raised questions about this view saying, "I wonder whether they needed to use all of their radar."

Seoul had claimed that the MSDF's P-1 plane flew just above the destroyer, an unusual move. However, the video shows the Japanese patrol aircraft flying regularly.

The video has proven the Defense Ministry's assertion that the plane kept at least the required distance of 150 meters from the vessel in accordance with international law and the Civil Aeronautics Act.

With regard to South Korean crewmembers' failure to respond to calls from the P-1, Seoul claims that crewmembers thought the P-1 was calling the security and rescue vessel because they heard the phrase, "Korea coast."

However, the video does not record the word, "coast," raising questions about the South Korean government's explanation.

At the same time, however, the video does not clarify whether the South Korean destroyer actually targeted the P-1 patrol aircraft with fire-control system radar. The video also does not show an indicator of the frequency of the radar waves or the strength of the signal.

The South Korean government has insisted that the destroyer was using radar for omnidirectional search on a different frequency instead of the fire-control radar. To dismiss this claim, Japan needs to disclose data such as the frequency of the radar waves.

However, the government cannot disclose such sensitive information. "If we disclosed that, we would reveal our search capabilities," said a senior official of the Defense Ministry.

While maintaining that there are limits to how far Japan can disclose such data, Defense Minister Iwaya said, "Needless to say, we gathered data on the radio waves and recorded it."

Toshiyuki Ito, former vice admiral at the MSDF, pointed out that the video that the ministry has disclosed is insufficient as evidence of Japan's claim that the P-1 aircraft was targeted by the fire-control radar aboard the South Korean destroyer.

"The video has confirmed that the P-1 wasn't flying at an alarmingly low altitude, but is insufficient as evidence because it doesn't record a warning sound showing that the destroyer targeted (its fire-control radar on the MSDF patrol plane)," he said. "Neither side can easily compromise in the dispute."

(Japanese original by Hiroshi Maetani, Political News Department)

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