If Tang Kingdom eliminates Zheng Kingdom and Tang borders Chu, it won't take long before a great war breaks out between the two countries.
Facing a Tang Kingdom that has taken control of an entire state and annexed Zheng Kingdom, the Chu soldiers in Yuzhou would be in an extremely bad situation if they had to confront them.
Even the territory they currently occupy would have to be slowly given up under the pressure from Tang.
That was unquestionably something Lu Yuan could not accept.
Therefore, slowing down Tang's aggressive advance and using Zheng as a shield to block in front was indeed a very cost-effective deal.
Given Tang's current reputation as universally despised among the neighboring nations, this state was fundamentally incapable of gaining recognition from other countries.
Even if things were indeed as Zheng had thought.