"Right" means opposite, and "base" refers to the fence around the barracks, generally referring to the fortifications for defense and vigilance.
To stand by and watch is to fight between the two sides and stand on the barrier.
From Sima Qian's Historical Records of Han Dynasty and Biography of Xiang Yu: "When Chu strikes Qin, you will see it from the wall."
When the Chu army attacked Qin Jun, the generals of the vassal states just watched and did not send troops to support them.
Extended data:
Watching is about the Battle of the Giant Deer in history:
After Zhang Han defeated Xiang Liang, he thought that Chu soldiers were not a worry, so he led the army to cross the Yellow River and defeated Zhao. The prince of Zhao took Chen Yu as the general and Zhang Er as the phase, and defeated the stag. Zhang Han led the king away and involved 400,000 people to besiege the stag.
At this point, the power of Qin Jun overwhelmed the vassal army; There are more than a dozen battalions of the vassal States that saved the giant deer, but they dare not send troops to attack. When the Chu army attacked Qin Jun, the generals of the vassal army watched in the camp.
Xiang Yu led all the military forces to fight Qin Jun nine times, and Zhang Han escaped. Xiang Yu led his army to attack Wang Li from the north. After the Chu soldiers beat back Zhang Han,
I saw the soldiers of the Chu army shouting ShaSheng earth-shattering, and the vassal soldiers were terrified. After defeating Qin Jun in this way, Xiang Yu summoned governors and generals.
When these generals entered Yuanmen, none of them walked on their knees, and no one dared to look up. From then on, Xiang Yu became the general of the vassal army, and all the vassals were under his command.
Xiang Yu burned his bridges, took the lead in conquering Qin Jun with dauntless spirit when the armies of the vassal states were bogged down, and drove the armies of the vassal states to destroy the king and leave the army at last, and forced 200,000 Zhang Han and Qin Jun to surrender eight months later.
Since then, Xiang Yu has established a leading position in various rebel armies. After World War I, with the army of Liu Bangxi Road breaking through Wuguan and Lantian, the main force of Qin Jun existed in name only.