If he Japanese government suddenly announced that they were rewriting their constitution to allow for the possession of nuclear weapons by the Japanese, this would end fairly quickly. The Chinese would suddenly feel a need to conduct military operations 'exercises' south of the Yalu River. The Russians might even join them, but probably not. That announcement by the Japanese should be coordinated with a sudden reactivation of the 2nd and 3rd Armored Divisions, and their announced placement in Poland and Slovakia.
That would get the attention of the Chinese and Russians. Back-channel announcements could be made to the Chinese and Russians that the deployments could be postponed, even permanently, if they 'restrained' the NoKos.