During the Northern Dynasties, the Northern Wei regime was in turmoil. General Erzhu Zhao killed Emperor Xiaozhuang Yuan Ziyou, installed Yuan Ye as emperor, then forced Yuan Ye to abdicate in favor of Yuan Gong. The Erzhu clan controlled the court with immense power. Ambitious Gao Huan secretly built his strength, waiting for the right moment to crush the Erzhu family. Soon, he raised an army against them, proclaimed Yuan Lang as emperor, and openly broke ties with the Erzhu clan. The two sides clashed at Hanling, where Gao Huan emerged victorious. Entering Luoyang, he deposed both Yuan Gong and Yuan Lang, instead installing Emperor Xiaowu Yuan Xiu.
In 532 AD, Erzhu Tianguang, who controlled the region west of the Tong Pass, regrouped and launched an attack on Gao Huan, leaving his younger brother Erzhu Xianshou to guard Chang'an. On the front, Gao Huan defeated Erzhu Tianguang and seized control of the imperial court. Seizing the opportunity while Chang'an was vulnerable, Yuwen Tai and Heba Yue, joined by Houmochen Yue, stormed the city and captured Erzhu Xianshou alive. This victory propelled Yuwen Tai's forces to rapid prominence.
Yuwen Tai, after carefully assessing the situation, saw that Houmo and Chen Yue were greedy and untrustworthy—a hidden threat that must be eliminated early to later deal with Gao Huan. He warned, "These men are treacherous; if we don't strike first, they will surely betray us." However, Heba Yue ignored Yuwen Tai's analysis and rashly led his troops to attack the distant Lingzhou governor Cao Ni. As a result, Heba Yue was ambushed and killed by Houmo and Chen Yue.
After Heba Yue's death, his troops were leaderless and panicked, with only Grand Commander Gui retrieving Heba Yue's body back to camp. Upon hearing the news, Yuwen Tai led his light cavalry to Pingliang, took command of Heba Yue's forces, and was warmly welcomed.
In 534 AD, Emperor Xiaowu of Northern Wei, Yuan Xiu, had long harbored resentment against the powerful general Gao Huan. Publicly, he announced a campaign against the Southern Dynasties, summoning troops from all provinces to bolster Luoyang's defenses, but his true aim was to force a decisive battle with Gao Huan. Secretly, he summoned the armies of He Bayue, Houmo Chenchong, and Chen Yue back to Luoyang. However, Houmo Chenchong and Chen Yue had already defected to Gao Huan and ignored the imperial decree. Meanwhile, Yuwen Tai had his own agenda. He stirred up his soldiers, declaring, "Houmo Chenchong and Chen Yue have wrongfully killed a loyal minister and defied the emperor's command—they are traitors to the state, and we cannot tolerate them!" The troops, burning with righteous fury, eagerly prepared to march against them. At the same time, Yuwen Tai sent a memorial to Emperor Yuan Xiu, explaining: "He Bayue served the state with utmost loyalty until he was unjustly slain. His soldiers have sworn to avenge him. Your summons to the capital is a wise policy, but Gao Huan's forces block us at the Hedong River ahead, while Houmo Chenchong's men cut us off at Shuilo behind—we are caught between two enemies. Moreover, He Bayue's troops are all from the Guanzhong region and long for home, unwilling to march east. I am wholly devoted to Wei, so I beg your leave to pause here and plan for the long term."
Emperor Yuan Xiu, seeking to counterbalance the powerful general Gao Huan, issued an imperial decree ordering the warlord Yuwen Tai to lead his forces against the rebel Houmochen Yue. Yuwen Tai, having sharpened his weapons and fed his horses for battle, crushed Yue's army in a decisive victory. From that moment, a deadly struggle for supremacy erupted between Gao Huan, Yuwen Tai, and the emperor himself, opening a brutal new chapter in their fight for control of the realm.
Later, the idiom "attacked from both front and rear" came to describe being under assault from enemies on all sides.
Source: *Book of Zhou*, "Annals of Emperor Wen I"
Meaning of the Idiom: Later, the Chinese idiom "首尾受敌" came to describe how being under assault from enemies on all sides.