North Korea: For the record. According to the Korean Central News Agency (KCNA), "the 1st Session of the 13th Supreme People's Assembly (SPA) of the Democratic People's Republic of Korea (DPRK) will be convened in Pyongyang on 9 April, Juche 103 (2014), according to a decree of the Presidium of the SPA on Wednesday."
Comment: As mentioned previously, the SPA is North Korea's legislature, but it convenes usually only twice yearly. Its primary role is to give government approval to laws, appointments and decisions made the Party. The new laws and appointments that the SPA approves sometimes help clarify the direction or emphasis of North Korean policy. In the aftermath of the execution of Kim's Uncle Chang last year, policy decisions have been more erratic and inconsistent than when he was alive.
China-North Korea: Today KCNA published that Wu Dawei, the Chinese Government's special envoy on Korean Peninsula affairs, and his party arrived in Pyongyang on 17 March. They were received at the airport by functionaries of the relevant sector and a counselor of the PRC Embassy in the DPRK.
Today the Chinese Foreign Ministry spokesman also mentioned Wu's visit for the first time. He told the press that Wu Dawei, the Chinese Government's special representative for Korean Peninsula affairs, visited the DPRK on 17 March and held consultations with the DPRK side. The main topics of the consultations were the situation on the Korean Peninsula and how to resume the Six-Party Talks, according to the spokesman.
Comment: The timing of the visit is significant. On 8 March, Chinese Foreign Minister Wang Yi announced instability and war on the Korean Peninsula constituted a "red line" for China. Subsequently, North Korea began holding a variety of rocket and missile firings off the east coast.
Nine days later Wu arrived unannounced in Pyongyang. His visit was not acknowledged until after it was completed. The statements provided no insights about the content or atmosphere of what appears to have been a brief visit.
Cumulatively, the circumstantial evidence suggests the Chinese leadership sent Wu to instruct the North Koreans about the meaning of China's "red line" as well as to clarify the meaning of the rocket and missile firings, if any.