"The Chinese ship ultimately unlocked its radar without firing a shot, but the incident underscores how the neighbors — wrangling over uninhabited islands in the East China Sea — are just one mistake away from potential armed conflict.
"Japan on Tuesday lodged a protest with the Chinese government over the incident, which took place near the contested islands that Japan calls Senkaku and China calls Diaoyu."
The row grew more heated in December when Chinese surveillance aircraft began flying near the islands. Tensions rose another notch last month, when Japan and China both scrambled fighter jets that briefly monitored each other.
Still, the recent radar incidents are among the first to involve naval warships from both nations, which had until now been kept in the background to avoid a dangerous escalation. With tensions so high, military experts in Japan and the United States say their biggest fear is some accident or miscalculation resulting in an unintended military confrontation.