The personal relationship between Chinese President Xi Jinping and Russian counterpart Vladimir Putin has been cultivated over years through shared activities like boat rides, birthday celebrations, and gifts.

Few relationships among world leaders have been portrayed as personally as that between President Xi Jinping and his Russian counterpart Vladimir Putin. Xi, who rarely publicly reveals much about his personal life or emotions, once described Putin as his “best and most intimate friend”. Over the years, their rapport has been defined not only by summits and state visits, but also a growing catalogue of highly personal rituals involving food, birthday celebrations, sports events, boat rides and...