With new leaders in South Korea, Japan and China, North Korea's nuclear test also fits another longtime pattern of a undertaking a provocative act early in the tenure of other political leaders, then following it with steps to smooth relations in hopes of persuading the others to provide financial aid and other assistance.

WSJ: North Korea Tests Nuclear Device

China, the world's second-largest economy, appointed a new President and Premier in March and the new leaders have taken over at a crucial time for the economy.

BBC: China's March trade deficit may signal key import shift