Can't find the title, but I found the GIF, this is Isao Machii- The Fastest Samurai of Modern Times, slicing a baseball in half.
When he was a child, Isao’s parents sent him to a martial arts school, because they believed that a real Japanese boy should at least try to become like a samurai.
When he was a child, Isao’s parents sent him to a martial arts school, because they believed that a real Japanese boy should at least try to become like a samurai.