BEIJING (AP) — With smiles and firm handshakes, North Korea and China used a surprise summit this week to show that despite recent tensions, Pyongyang still has a powerful backer and Beijing will not be sidelined in discussions about the fate of its unpredictable neighbor.

North Korean leader Kim Jong Un's secretive talks with Chinese President Xi Jinping in Beijing — which were not confirmed until after his return home — appear aimed at improving both countries' positions ahead of Kim's anticipated meetings with South Korean President Moon Jae-in and U.S. President Donald Trump in the coming...