Chương 654: Secondary Communication

Information and reconnaissance were not easy, but he had patience.

If he couldn't do it in a year, he would do it in two years, three years, four years or five years… The fragmented information was tested and confirmed several times before being perfected bit by bit.

Yu Youyao was in disbelief. "Cousin, you're really thorough."

He had even investigated the topographic map of the grassland. This was something that even Emperor Gaozu had not done back then. Otherwise, the north expedition would have ended quickly.