抗日战争时期，国民党、共产党建立了第二次国共合作关系。为了一致抗日，蒋介石把全国划分成了五个战区，后增加到九个战区。第二战区长官司令部的驻地就在壶口东岸的克难坡。时至今日，其他战区的遗迹早已荡然无存，唯有克难坡这个山巅小城堡成了全国仅存的一处抗战时期战区? During the War of Resistance Against Japan, the Kuomintang and the Communist Party established the second cooperative relationship between the KMT and the CPPCC. In order to unite against Japan, Chiang Kai-shek divided the country into five war zones and later increased it to nine war zones. The station headquarters of the Second Theater Chief Commander was Kelupo on the east bank of Hukou. Today, the ruins of other theater have long gone, only Kelapo this hilltop castle has become the only one in the war zone during the war of resistance?