Yami Qaghan[1][2][3] (Old Turkic: 𐰖𐰢𐰃:𐰴𐰍𐰣 Jаmï qağan;[a] Chinese: 啓民可汗, 啟民可汗/启民可汗; Pinyin: Qǐmín Kěhàn, Wade-Giles: Ch'i-min K'o-han, Middle Chinese (Guangyun): [kʰiei˥mi̯en˩ kʰɑ˥ɣɑn˩˥]), personal name Ashina Rangan (阿史那染幹/阿史那染干, pinyin Āshǐnà rǎngān; Wade-Giles A-shih-na jan-kan, [ʔɑʃi̯ə˥nɑ˩ nʑi̯ɛm˥kɑn˩˥]), at one point known as Tolis Qaghan (突利可汗, 𐱅𐰇𐰠𐰾𐰴𐰍𐰣, Töles qaγan) and later El Ïduk Jamï(r) Qağan[8] (意利珍豆啟民可汗/意利珍豆启民可汗, Yìlì Zhēndòu Qǐmín Kěhàn) was the first qaghan of the Eastern Turkic Khaganate.
Tulan started to gather invasion party to attack Sui repeatedly in 597 and 599, only to be reported to emperor beforehand by Tolis every occasion.
Meanwhile Tulan was killed by his men causing Tardu to assume throne and claim title Bilge Khagan in 599/600.
In winter 601, Emperor Wen commissioned Yang Su to command an army, in association with Qimin Khan as to attack Tardu.
Having a cleared way Qimin assumed Turkic throne, definitely starting division between Western and Eastern wings of khaganate.