Michael Crowley writes for Time about the hostility felt by China towards Japan, a feeling reciprocated to a considerable extent. Japan occupied much of Eastern and Southeastern Asia before and during World War Two, including Korea and much of China.
As we've noted before in this space, Japan left behind few friends in the lands they occupied. The Chinese, the Koreans, the Filipinos, even the Chamorros on Guam harbor negative feelings about Japanese rule. The one exception may be Taiwan where, for reasons unclear to me, some pro-Japanese feeling remains.
Crowley wonders if the mutual dislike felt by Chinese and Japanese can lead to war in the region? For sure, it doesn't help defuse any situations that develop.
In spite of residual anti-Japanese feelings, I believe most regional nations (except North Korea) would reluctantly side with Japan in any conflict. This because in the last decades, only China has been acting like the playground bully. It's been almost 70 years since Japan acted badly toward its neighbors.