Xi Jinping and Vladimir Putin have long been keen to portray their respective nations as allies, united in the common goal to roll back Western global dominance.
Since the war in Ukraine began, China has sought to position itself as something of a neutral ground setting out a 12-point peace plan in February.
Fears, however, have been increasing that China could be covertly supplying weapons to Russia, a speculation that has angered Xi's Western counterparts.
European Commission head Ursula von der Leyen warned that "arming the aggressor is a clear violation of international law - he should never be armed", in a much-anticipated visit to China in April.
Now, however, as the war rumbles on and speculation surrounding Putin's ill health or a possible coup mounts, experts have said that Xi might be implementing further steps to pave the way for a continued partnership post-Putin.
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According to one analyst, Xi is thought to be seeking to form closer relations with potential successors to the Russian president.
In a blog post for the US think tank Atlantic Council, senior fellow and regional expert Anders Åslund argues that Xi appears to be seeking to cultivate closer ties with Putin's potential successors.
In particular, he points out that the recent summit where Xi visited Putin in Moscow - and squeezed in a rare one-on-one with Russian Prime Minister Mikhail Mishustin.
Then, in May, China's Prime Minister Li Qiang invited Mishustin to China, making him the highest-ranking Russian official to visit China since the start of the Ukraine invasion and what Åslund called "completely beyond the ordinary bounds of Chinese and Russian protocol".
Åslund continues: "If there is a greater stickler of protocol than the Chinese leaders, it is probably Putin.
"In spite of all the greetings to and from Putin that Xi and Mishustin exchanged, the obvious question arises: Why was Mishustin invited and not Putin? This cannot have gone down well with the Russian leader."
Mr Åslund argues these recent events are "perhaps the best evidence we have that China may be looking beyond Putin and seeking to cultivate alternative relationships in Russia".
Mistushin is not commonly referenced as a potential Putin successor - but this could, in turn, be a strategic move on Xi's part, too.
Mistushin has a reputation as a sound and effective manager. He has, according to Russian media, played "no part" in implementing Putin's war, and will not discuss it.
If, as China's ambassador to Russia said last month, China's tactic truly is to "call for peace and promote negotiations", the milder prime minister might be a desirable ally.
Speaking to Insider, Ali Wyne, an analyst with the Eurasia Group in Washington, DC, said that given rumours about Putin's health, and potential challenges to Putin's power, it made sense for China to be engaged in "contingency planning".
He said: "Governments regularly engage in contingency planning; that activity does not necessarily indicate strategic preferences," he said.
"Given ongoing rumours about Putin's health and speculation that a Ukrainian defeat of Russia could undermine his rule, many countries-including the United States and China-are likely envisioning various post-Putin futures and weighing the implications of each for Russia's domestic politics and foreign policy."