Chinese warplanes — including advanced fighters and nuclear-capable bombers — have conducted more than 150 sorties into airspace near Taiwan in the first five days of October, setting single-day records on three of those and raising the specter of military miscalculation.

The incursions into Taiwan’s air defense identification zone (ADIZ) — which differs from sovereign airspace — and the confusion over the moves’ intended signals have unleashed a flood of concern in both Washington and Tokyo. The two capitals both view Taipei as a crucial, albeit informal, partner in combating Beijing’s attempts to change the status quo in the region via coercion.

But the latest flights, as well as other moves coming out of Beijing, Washington, Taipei and even Tokyo, have been especially concerning as the Sino-U.S. rivalry pushes the two powers’ relationship to its lowest point in decades and triggers fears of a new Cold War that would envelop all four capitals.