This is an apolitical forum for discussions on the Axis nations and related topics hosted by Marcus Wendel's Axis History Factbook in cooperation with Christian Ankerstjerne’s Panzerworld and Christoph Awender's WW2 day by day.
Founded in 1999.
I'd go with Iwane Matsui, primarily because he accomplished what he set out to do; take Nanking. He also destroyed Chiang Kai-Shek's best divisions in Shanghai, which had an impact on China's war effort. Of course, Matsui taking Nanking didn't end the war, but that is mainly a political matter.
It appears to me that the the destruction of the Chinese forces was more a result of superior Japanese training, firepower etc than excellence in generalship. After the cream of the Chinese forces were decimated in the Battle of Shanghai, it was not all that hard to pursue the remnants fleeing in disorder. Nanking was poorly defended and the resulting battle was a fiasco.