The three Qin armies advance. But following what strategy?

The army of General Ousen advances rapidly toward Retsubi, which opens onto the State of Zhao. According to tactician Shouheikun, the conquest of this city is essential to Qin's future, just like Gyou, the centerpiece of upcoming operations and the stake in the strategic duel between Riboku and Ousen... How will the situation evolve? Both sides hold their breath.