Tsukahara Bokuden founded the school of Kashima Shinto Ryu in the 15th century. He was a well-respected man, known for his swordsmanship. Back then, it was customary for swordsmen to travel across Japan and learn techniques from different dojos. Lessons were learned, techniques were spread. Men who knew the art of the sword were treated well by everyone, and not because they could easily cut off your ears.
Tsukahara traveled with a large entourage of students. One evening, they were on a boat for a party, having a good time. A drunken ruffian walks up to Tsukahara and asks what style of sword he uses.
"I use the style of no sword," Tsukahara told him.
The ruffian didn't believe him. "I challenge you to a sword fight," he said.
They agreed that a fight could not happen on the boat, so they found an island nearby. The ruffian was the first to disembark, and Tsukahara ordered the boat to cast off without him. And so Tsukahara tricked the ruffian into spending the night on an island in the middle of the lake, without a fight.
In Kendo, you do not seek out fights. You only fight when you have to. Tsukahara didn't have to fight the drunk ruffian, so he didn't.