Originally Posted by
Nathan Scott
From my training and experience, kesagiri (a diagonal cut) is a more natural cut to execute..
A straight cut requires more training to perform correctly, due largely to equalizing the strength relationship between both grips to ensure proper hasuji throughout the cut...
So in closing, my analysis indicates that straight cuts are, in many regards, the mark of a more advanced system of swordsmanship and training, while kesagiri is largely the mark of a system that was more tailored towards quickly teaching the masses an effective method of swinging that can be used with or without armor. This is probably the main reason kesagiri was found to be the cut of choice on the battlefield.
To be clear - both have a great deal of merit, so I'm not implying that arts that favor kesagiri are low class, as much as the context and intent of the teachings may be different from a historical standpoint.