I personally interested Kendo philosophy more that Kendo techniques.
All Japanese martial arts such as karate, kendo, and judo have same based philosophy. It is a personal development mentally, physically, and spiritually.
There is a famous word "kenshin ichinyo"in Japanese among Kendo players.
"ken" means sword, "shin" means heart, "ichinyo" means 1D (one-dimensional)which means when you play Kendo, you have to have harmonize or accommodate heart and sword.
What a beautiful spirit!