当时戚继光带来的一批义乌兵成为修长城的主力，大约在明朝隆庆三年起，组织兵卒在东起山海关，西至北京昌平县西的镇边约一千公里漫长的长城线上大兴土木，到隆庆五年，，竟一口气筑起了1917座空心敌楼，(又称空心敌台)，后来到了万历三年(1575年)增至1337座。
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