Drone footage that circulated on Chinese social media showing a Japanese warship docked at a military base has revealed worrying gaps in Japan’s defences, analysts say - though combating the threat may not be easy. The 20-second video, which was posted to Chinese video-sharing website Bilibili on March 26, shows the helicopter destroyer Izumo of Japan’s Maritime Self-Defence Force moored at Yokosuka naval base in Kanagawa prefecture.