On this day, 81 years ago, July 22, 1944 (June 3, 1944 in the lunar calendar), the US military observation team arrived in Yan 'an. Mao Zedong (front row right 1), Zhu De (front row left 4) and others took a group photo with some members of the US military observation team in Yan 'an. On July 22, 1944, the U.S. military observation group headed by U.S. Colonel Bao Ruide arrived in Yan 'an at the dispatch of the U.S. General Command in China. On August 7, the second batch of members of the US military observation team flew to Yan 'an. Their main task is to observe and understand the combat conditions of the Eighth Route Army and the New Fourth Army behind enemy lines, and to establish contact and cooperation with them. Ye Jianying, Yang Shangkun and others were greeted at the airport, and were later received by Mao Zedong, Zhu De, Zhou Enlai and others. Peng Dehuai and Chen Yi respectively introduced the general situation of the Anti-Japanese War behind enemy lines of the Eighth Route Army and the New Fourth Army. In addition to visiting Yan 'an, the US military observation team later sent some members to the anti-Japanese base areas such as Shanxi-Chaji and Shanxi-Sui for on-site inspections. During the visit and inspection, relevant personnel of this group wrote many investigation reports, which objectively reflected the political, economic and military situation in the anti-Japanese base areas and the principles and policies of the Communist Party of China. The report of the US military observation team also made suggestions to the US government that it should attach importance to the Communist Party of China and its armed forces. Zhou Enlai took a group photo with Bao Ruide, leader of the US military observation team. Zhu De and others took a group photo with members of the US military observation team in Yan 'an