What holiday is January 31st?

January 31, 1949 Pingjin Battle ended victoriously and Beiping was peacefully liberated. from January 14 to 15, the Northeast Field Army launched a general attack on the defenders of Tianjin who refused to surrender, using infantry, artillery, engineers, and armored troops of all types of combat, and totally annihilated 130,000 defenders after 29 hours of fierce fighting, liberating Tianjin. After the liberation of Tianjin, the People's Liberation Army (PLA) with an army of 900,000 troops was at the foot of the city of Beiping. Under the heavy deterrence and political struggle of the PLA, and with the strong promotion of the underground party and patriotic democrats in Beiping, Fu Zuoyi, the commander-in-chief of the North China "General Suppression Army", led his troops to accept the peaceful reorganization in the second half of January and drove them out of the city from January 22nd to 31st one after another to wait for the reorganization. The Northeast Field Army then entered Beiping to take over the defense of the city, and on February 3, the People's Liberation Army (PLA) held a grand entry ceremony into the city of Beiping. In the Battle of Pingjin, the PLA, with 39,000 casualties, annihilated and reorganized 1 enemy headquarters, 1 police headquarters, 3 corps headquarters, 13 army headquarters, 51 divisions (including two cavalry brigades), **** more than 520,000 people. Thus, in addition to Taiyuan, Datong, Xinxiang, Anyang, as well as the intention to temporarily save the present-day Hohhot, all of North China was liberated.