Vice President Joe Biden urged Japan and China last week to set up "effective channels of communication" to avoid a dangerous escalation in their increasingly fraught dispute over maritime territory. But the estrangement between the Asian powers is so deep they are barely talking.

Prime Minister Shinzo Abe and Chinese President Xi Jinping, both in office for roughly a year, have spoken just once — for a matter of minutes. The Japanese and Chinese foreign ministers haven't held formal talks in 14 months. Contact between their coast guards and militaries is zero.

"There used to be so many channels" of communication, said a senior Foreign Ministry official in Tokyo, speaking on the condition of anonymity to discuss sensitive information. "But that has all but stopped."