战国,是我国刀戟相加,诸侯混战的时代。各诸侯国为保自己边塞要地,在与邻国接壤地区,挖堑筑壕御守疆土。闻名中外的古长城于是乎就修筑起来。 战国七雄中,燕国地处北部边陲,国小力薄,又有腹背受敌之患。燕初,常为北邻东胡强族所侵扰,至燕昭王(公元前311年至公元前279年)时,燕王励精图治,国威大振。昭王十二年(公元前300年)转守为攻,对东胡发动了强大的军事攻击。《史记 Warring States, is China’s knife halberd addition, princes melee era. The vassal States to protect their own border areas, bordering the neighboring countries, digging cut trench dugout territory. The ancient Great Wall, famous both at home and abroad, has since been built. Among the seven male warriors in the Warring States, Yan State is located in the northern border area, with a small state of power and an afflicted area. In the early days of the reign of Yan, it was often invaded by the Beiju and Hu tribes in the north. When Yan Wang (311 BC to 279 BC) was invaded, the Yan Wang rejuvenated and the state preached. In the twelfth year of King Zhao (300 BC), he turned to defend and launched a powerful military attack on Donghu. "Historical Records