Blue's Kendo training

When Chuck trained Blue he made Blue learn kendo so he would be able to fight Pokémon on his own. He had Blue fight a large Pokémon using only his wooden sword. Chuck stood by while Blue beaten again and again by the Pokémon so he could team Blue the suffering that Pokémon faced in battle. Blue’s kendo practice taught him several lessons that make him invaluable as a trainer. After all, kendo is a form that is beneficial for the health of both the mind and the body. Kendo teaches values including discipline, preparation, and a love for the intensity of battle.

Even if you don't slice through at first Blue, remember, your mind and body will both grow and when you can feel the essence of the enemy, then and only then can your Pokémon feel the will of their trainer. (Page 11, Chapter 52)

Blue’s kendo made him disciplined, if he doesn’t reach his goals on his first attempt he will continue trying until he succeeds. Blue works to complete his Pokédex without breaks and even buys an “extremely hard to train” Porygon so he has one more Pokémon in his Pokédex. Blue works tirelessly until he is able to make Porygon an integral member of his team. Blue is always prepared for a battle. Even when he doesn’t expect to face enemies he can always beat down unexpected enemies and often uses his surprise at a way to catch new Pokémon, such as a Lapras near an abandoned power plant. Finally, Blue loves to battle, that’s part of why Blue became a Gym Leader.