Daga can, Changchun ya wuce zuwa Balasagun da Kogin Shu, kuma a ƙetaren wannan kogin zuwa Talas da yankin Tashkent, sannan a kan Syr Darya zuwa Samarkand, inda ya tsaya na wasu watanni. A ƙarshe, ta hanyar Iron Gates na Termit, a kan Amu Darya, kuma ta hanyar Balkh da arewacin Afghanistan, Changchun ya isa sansanin Genghis kusa da Hindu Kush. Tambaya: Ina Changchun ya isa?
Sansanin Genghis