To be fair The Chess is a lesson in why assassins are cool, hypothetically. If you have to regime change the enemy, sending a ninja spares the lives of a lot of soldiers and officials.

The problem is sufficiently skilled ninjas are hard to come by. German tried around forty times to kill Hitler, and he very much needed assassinatin'. But all they had were timid officers and a few people with skills. Even the July 20 Plot famously failed.