I loved this chapter but I will echo some other comments about where this argument is going. I really, really disliked it when manga authors try to become overly deep or philosophical. It often ends up feeling contrived and forced. If they show Kanki's insanity despite his brilliance I will be fine with whatever he says. But if they string together an argument that Shin is a hypocrite then I will be annoyed.

I am all for areas of gray area vs. black/white thinking. However there is no gray areas here. The massacre of civilians has always been as one of the worst atrocities of war. Any time period, in any history. You do not murder civilian populations. I have a feeling the argument will be 'if I can end a war faster, even if we kill civilians to further that goal so be it. Better than prideful generals who throw thousands of lives away like a game.' Contrary to this argument the manner in which a war is won matters greatly. War needs consequence. Both sides need to feel the pain of war. They basically spelled this idea out with the Zhao general (Mangoku?). There is something to be said about mass loss of life on a battlefield as opposed to loss of civilian life. The latter will reverberate longer and louder in the minds of the populace. The difference between those willing to fight and those who do not. For fucks sake his men are murdering old women and children. Raping civilians and destroying villages. What philosophical spin is the author going to put on that one? 'No really it's better this way. (?) The civilians would thank me. (?) This isn't easy for me either. (?) Traditional generals are the biggest villains'

Finally this idea that countries that lose a war is a death sentence for civilians is such a terrible rebuttal. You know what is a death sentence for civilians? Being raped and murdered. Civilians have lived through the changing of hands between states and powers for as long as history has been. You know what makes a people resistant to change? Genocide. Unspeakable atrocities. How you conduct a war and the principles you set during it will have long standing repercussions afterwards.

TLDR - You do not murder and rape civilians. Period. 'This is war' is a cope out answer for the broken. The only way the author can go with this is to explain why Kanki is insane and to illustrate why despite his genius he will not be one of the 6 great generals. (I don't follow the Chinese history this is based off of)