On 2018 Dec. 20 The Japan Maritime Self-Defense Force (JMSD)’s patrol aircraft conducted a threatening low-altitude flight for a considerable duration over ROKS Gwanggaeto the Great destroyer, which had been conducting a humanitarian rescue operation for a North Korean fishing vessel in distress. The aircraft made a threatening “8-shape” flight by continuously flying with 500-meter distance and 150-meter altitude. 150m is the lowest altitude for safety even without any people or buildings present. Japan claimed that it had conducted the flight to observe what operation ROK ship was conducting and the crew was not aware of the rescue operation. However, it is questionable that Japan was unaware of the situation. In the video released by Japan’s MoD (Ministry of Defense), the aircraft crews mention two coast guard rubber boats and a wooden ship in distress. In common sense, it is hard to say that they did not recognize the situation.
 Despite the threatening low-altitude flight, ROKS Gwanggaeto the Great destroyer identified the aircraft as a friendly one using its IFF (identification friend or foe) and confirmed its friendly status using an optical camera. However, Japan argued that ROK Navy illuminated STIR radar, a radar for fire control and other precise detections, to its patrol aircraft. However, the ROK Navy has no reason to illuminate an identified friendly aircraft with such threatening tracking radar. Illumination of the radar can be clearly verified once Japan’s MoD provides precise radar frequency data, but Japan is not willing to disclose the electronic support measures (ESM) recorder’s data saying that its patrol aircraft’s radio wave collection capacity may be exposed. Rather, they are suggesting that the ROK MND (Ministry of National Defense) reveal full frequency specifications of the ROK Navy’s tracking radars to verify unidentified radar frequencies that the JMSDF patrol aircraft collected. This is a highly inappropriate attitude towards friendly nations since the frequency specifications of tracking radars are highly sensitive and classified military information. Disclosure of such radio frequency would mean the exposure of the critical secret of the Korean warship’s weapons system while the showing of Japan’s ESM recorder data would just mean a partial disclosure of its patrol aircraft’s capacity.
 Even after this first incident, JMSDF’s patrol aircraft continued to conduct low-altitude flights toward ROK ships, and on Jan. 21 it marked its 4th provocation. Reserved personnel from the ROK Navy argued that to put things to their advantage Japan is trying to induce the use of fire control radars by continuing such provocations. Others say Japan is aiming for the full frequency specifications of the ROK Navy’s STIR, which may lead to the emasculation of the antiaircraft fire function of ROK ships.
 In May 2017, Japanese Prime Minister Abe set a 2020 deadline for revising Article 9, which renounces war as a sovereign right of the nation and restrains using force as means of settling international disputes, so that Japan would be capable of war when they want. However, now that North Korea is trying to keep a peaceful relationship with the United States of America, Japan’s anti-North Korea sentiment is weakening. Also, Japan has recently shown a gesture of reconciliation with China. In this condition, Japan’s only way of justification for its rearming would be the military tension with Korea. Just as the Minister of National Defense, Jeong Kyeong-doo claimed on Jan. 23, Japan may have a political background behind this provocation towards Korea.