Their Emperor used Zhou's grain to support the people of Xiliang. Despite the difficulties, as the Minister of Revenue, he complied because he knew the Emperor's goal was the unification of the nation. The Emperor already treated the people of Xiliang as his own.
Now, if Zhou were to go to war with the Yan Kingdom, the issue of supplies... this would indeed be a monumental challenge for him.
But challenges must be met. Sitting in the position of Minister of Revenue, if he doesn't solve the problems, what does the Emperor expect him to do? He can't just throw up his hands and complain to the Emperor about being poor!
Moreover, given the current situation, the Emperor had just put the Prince to sleep and would leave the city once awakened. Even if he were to cry poverty, there would be nowhere to cry to. He still had to find a way...
After much contemplation, he felt he might have to target the businesspeople within Zhou's borders.
