Legend has it that while roaming the wooded hills around his village one day, Yagyu Munetoshi encountered a tengu — a mythical creature, part human and part bird, adept at swordplay.

Munetoshi was renowned for his fencing skills and relished the opportunity to duel with such a foe. When he sensed a weakness in his opponent's guard, he attacked with a thunderous bellow. Just as his sword was about to strike the tengu's head, it disappeared; the sword instead struck a large rock, which it cleaved in two.

I stood in the dark forest looking at the stone that spawned this legend. The muddy ground squished as I moved closer. The rock was much larger than I had expected it to be — but it was most certainly split cleanly into two parts.