This electromagnetic wave manipulation was absolutely established until 1980s, which basically meant the Soviet Union should have possessed its capability in those days. It also implies Russia is capable of conducting an electromagnetic operation.
Although, their operational depth toward Japan has completely changed since the collapse of USSR. Russia is still the nearest geographically to Japan, but they do not need to support Japanese left extremists anymore, who were affiliated with the Soviet communist league in those days. The left extremists are the same as before, but the Russian government now has a free hand to negotiate with the Japanese mainstream.
China also has this technology, which cares more about the relationship with Japan as traditional neighbors for thousands of years. Their concern appears sometimes as an intelligence operation in Japan, though it is not that easy to employ this technology in Japan. Their technology is assumed to be advanced as highly as the CIA, but they need to hire native Japanese speaker for this operation in Japan, as the individual brain is used as a medium to send and receive a message by the wave.
It is actually not an easy task to hire many Japanese as an asset. There are many Japanese who study English or who has the capability to speak it, but there are not so many people studying Chinese. American cares English speaking capability, as they would like to share assets within the agency.
If the asset just speaks Japanese, this individual follows an order of the specific officer, which might create a disturbance in the future operation, sabotaged by the personal interest. This reality is the same to China that their intelligence prefers someone who has a command of Chinese, and if not, the asset should be ruled by the specific officer, which creates a dangerous flaw.
Furthermore, if you become a Chinese spy, you are marked by the Japanese police intelligence for sure, hence it is hard to maintain that status. All in all, there are still some walls to climb over for the Chinese intelligence. At the same time, the electromagnetic wave is invisible, but it can be traced actually. It means they can operate some plots in Japan, but not far-flung due to many obstructions.
It is North Korea that has penetrated more into the Japanese society and their relation to the Japanese government is incomparably so worse that they should conduct more social and political operations in Japan. Their independent operation should be captured especially when it takes a long time to run as there is a way to find it out if the police or any other intelligences decide to trace the invisible wave.
However, if their spies work as a double spy in Japanese organizations, such as working as an asset to the Japanese police intelligence, the police does not care how they work as they are assumed to be their affiliates. This holds true to the CIA that if double spies work as contractors to the agency, their rogue operation is assumed insubstantial as the agency believes they are under control. However, the reality is not, some of their operations are purely conducted for North Korea.
Moreover, it is easier for North Korea to find Japanese native speaker working for them, as there are many their nationals and descendants living in Japan. Some of them are actually blackmailed that their relatives are going to be sent a notorious North Korean prison if they are not helping them. In this way, North Korea has more capability to run a covert operation against Japan as a double spy of other intelligence organizations. There have been many operations conducted in Japan with a trace of North Korean intention as a result.
Japan is geographically unique for its surroundings, but you might get some ideas how the foreign intelligence work in your own country.