Months into the Russian invasion of Ukraine, another, invisible war is becoming apparent — the war in cyberspace. As Russia had launched cyberattacks on Ukraine's infrastructure before the invasion, Ukraine responded with its newly formed IT Army, calling for volunteers from around the world. More than two hundred and fifty thousand people have already joined, targeting Russian government functions and private companies with DDoS attacks and other tools. However, the civilian volunteers risk breaking the law in their own countries and even harming innocent people through the attacks. We take a look at the risks connected to this new type of warfare. Guest: Tsuchiya Motohiro (Professor, Keio University)