of the Second Eastern Turkic Khaganate commanders Tonyukuk (646-724) and Kul Tigin (684-731).

The first to attempt to decipher the name of the Irtysh was the Turkic philologist Mahmud al-Kashgari (1029-1101). According to his interpretation, the river got its name from the word ertishmak (quick jump). At the same time, according to the legend cited by his contemporary,