Kodama is a very old belief, and a very old word. It was spoken long before Japan had a written language. What exactly a kodama is has changed over the centuries, from nature gods to goblin spirits. In ancient times, kodama were said to be kami, nature deities that dwelled in trees. Some believed that kodama were not linked to a single tree but could move nimbly through the forest, traveling freely from tree to tree. Still others believed that kodama were rooted like the trees themselves, or in fact looked no different from other trees in the forest. But they were also a sound. Echoes that reverberated through mountains and valleys were said to be kodama. The sound of a tree crashing in the woods was also said to be the plaintive cry of a kodama.