Nakayama Hakudo is one of the greatest swordsmen of 20th century Japan and the father of iaido. He coined the term. Hakudo was active both before and after World War II. One of Hakudo’s key teachings is that regardless of what occurs—in Hakudo’s case the devastation of war and the defeat and occupation of his country—a martial artist has to deal with the situation in a positive manner and freely adjust to the circumstances. That is the one of the messages of the Heart Sutra: don’t get caught up in external trappings or hard-and-fast opinions.
Hakudo was also an artist with the brush, one of the best calligraphers of his time. His version of the Heart Sutra—considered one of the best tests of a calligrapher’s skill—moves up and down the paper boldly and without any hesitation, the same way one should utilize a sword. Not the sword that kills but the sword that gives life. This particular Heart Sutra was dedicated to Kannon, the Bodhisattva of Compassion.