The tensions created by the United States’ trade war with China and Beijing’s territorial claims in the South China Sea, and American pushback, pose challenges for closer ties between their militaries. Evidence of that is the US exclusion of China from last year’s Rim of the Pacific Exercise, the world’s largest multinational naval war games, in retaliation for claimed militarisation of the South China Sea. As a result, unfortunately, the two nations missed an opportunity to build the trust and cooperation fundamental to avoiding mishaps and misunderstandings. Any development that is positive for operational cooperation, no matter how small, is therefore welcome. And if it has a humanitarian element all the better. An example is the participation of the China and US militaries in an annual joint disaster relief training exercise for the seventh consecutive year. Chinese troops head to Hawaii for joint disaster relief exercise Now under way in Hawaii until November 24, it involves more than 200 personnel from the People’s Liberation Army’s Eastern Theatre Command and the US Army Pacific. It is not an isolated instance of military or law enforcement cooperation for mutual civilian benefit. Another to be hailed recently resulted in a suspended death sentence and eight jail sentences for Chinese traffickers in fentanyl , the drug at the centre of the American opioid crisis. These may be relatively small collaborations that are not to be compared with senior military exchanges, or international naval exercises to improve partnerships and enhance readiness and communications. But cooperation between the rank-and-file of the military branches at any level makes for effective operational relations. It is from experience at both levels that relationships and practices that make cooperation easier in times of crisis can be developed. Improved communication and trust-building comes not just from talk, but working together at a practical level. Sooner or later these qualities could make the difference between life and death in disaster relief cooperation.