Unlock Dong Faction in 5 turn without cheat and save file (update latest patch 1.7.0)

Play Ma teng faction and choose easy mode, You get 8000 gold starting

1st turn as usual fight the yellow rebel and move back to you base for replenish.
Optional : you can trade all your begin ancillaries for extra gold. i got 3k from han sui + han empire by selling my accessories .
Before end turn declare war with dong.
2nd turn . Recruit your troops and get a strategist from pool and get trebuchet .
GO get san pass . than recruit hua lan li . End your turn
During ai turn , you should see li jue moving to han zhong
3rd turn. Move hua lan li outside the line as bait. Ma teng go behind her and use ambush stance. Save. End you turn
AI should now attack hua lan li . FIght the battle. Kill their general and try to let their army flee. You cannot kill guo si, must let him leave.
You only need to kill Niu fu. You need to release Li jue and Guo si . If you do correctly, dong zuo should spawn now . Happy hunting

Note: if you can't get strategist in turn 2 , just get other type of candidates and march to san pass to siege . and follow next step.