Japan’s call to maintain “impeccable” defences on its northern frontier reflects Tokyo’s deepening concern over growing Russian military activity in the region, analysts say. They also point to rapid north-south troop deployment exercises as preparation against a potential “diversionary operation” around Hokkaido: a scenario in which Russia could open a second front if Japan were already focused on a crisis with China in the south. During a visit to military bases in Hokkaido on Saturday,...