The Esan map in the OP used five colors, while four would be enough.
https://en.wikipedia.org/wiki/Four_color_theorem
Even worse, Nong Khai and Bueng Kan have the same color.
All provinces have the same name as their capital (not necessarily the largest town, e.g. Songkhla / Hat Yai). When asking boys where they come from, I sometimes get the province name, sometimes the region of Thailand.
In rare cases, I get a simplification. A boy from Ang Thong said he is from Ayutthaya, but when I asked for the district, he said he is not from Ayuatthaya but Ang Thong, but thought I wouldn't know where Ang Thong is and his home district borders on Ayutthaya. I have been around to so many places, I often ask for district as well. That weeds out foreign boys as well; I'm not good at recognizing accents, so a boy from Cambodia could pass as coming from Surin, but when I ask for his district, the truth will come out.