Southern Song–Jin Standoff

Timeline

1. 1221Huai River defense line · Jianghuai regionAfter the Jiading peace collapsed, Song-Jin fighting had already lasted several years. Around 1221 the Southern Song deployed heavy forces along the Huai West and Huai East lines, using fortresses and waterways to resist Jin's southward advance; though Jin repeatedly attacked, it could not break the Huai–Yangtze defense in depth, and neither side changed the strategic picture.
2. 1221–1222Jin-ruled territories · North ChinaMongol forces were at this time attacking around Jin's capital Zhongdu and in Hebei and Shandong, drawing Jin's troops and funds northward. Though Jin maintained an offensive posture on the Song border, it could hardly organize a decisive southern campaign, and the Song-Jin front settled into a war of attrition.
3. 1222East Asia · East AsiaBy around 1222 the Southern Song held Jiangnan, Jin was confined to the Central Plains under constant Mongol blows, and the Mongols had not yet clashed head-on with the Southern Song, forming a delicate strategic balance. Unable to recover the Central Plains, the Southern Song maintained its partial security through the Jin-Mongol struggle, a balance that would shape later diplomatic choices.