A column on the real estate site LIFULL HOME’S advises residents of Japanese apartment buildings not to deal with a noisy neighbor directly. Direct dealings between residents, it says, can cause further trouble. The best way is to go through a third party, such as the management company.
The management company then usually puts up a notice or puts a letter in the mailboxes. A real estate blog adds that the warning is often addressed to all residents, not to one particular resident.