Fig. 1: Geographical locations of relevant sites.

The red and black dots represent sites where late Shang remains associated with horses have been discovered. Dots within the blue region correspond to sites of the Shang culture, while those within the red region indicate sites belonging to its neighboring powers. The yellow triangles denote the locations from which the reference samples come. (1: Yanjiagou; 2: Anyang; 3: Xujianian; 4: Yujiawan; 5: Nianzipo; 6: Hejia; 7: Heidouzui; 8: Laoniupo; 9: Xicha; 10: Linzheyu; 11: Xinzhuang; 12: Zhaigou; 13: Lijiaya; 14: Waizhuangcun; 15: Caojiayuan; 16: Shangdongcun; 17: Jingjie; 18: Qiaobei; 19: Jiuwutou; 20: Xiaohucun; 21: Tianhu; 22: Ximufo; 23: Beizhuangzi; 24: Chenshantou; 25: Houqianyi; 26: Donghangezhuang; 27: Liujiazhuang; 28: Subutun; 29: Qianzhangda; 30: Lijia; 31: Zaolinhetan; 32: Heimugou; 33: Peijiamao; 34: Houma; 35: Guanzhuang).