At this week’s Shanghai Cooperation Organization summit, Vladimir Putin and Xi Jinping seemed determined to show the whole world that Russia-China relations are better than they have ever been. Since Russia’s invasion of Ukraine, China has become Putin’s most valuable ally, both in diplomacy and on the battlefield, providing dual-purpose technology for Moscow to continue its aggression. Are Sino-Russian relations really at their peak? What can the history of the USSR and China teach us about the nature of this union? How strong is the bond between the two?