Hitting a baseball is one of the most difficult things in all of sports. In the span of 60 feet and six inches, you have to determine how fast a ball is going, how it is breaking, and when you have to swing your bat to make contact. When a ball is going 100 miles per hour, you have 0.412 seconds to process all of this information and react, which goes to show how difficult it is to hit a baseball.
Some guy in Japan laughed at this and decided that he was going to take a samurai sword and slice a 100 mph heater cleanly in half. After watching two baseballs go flying by him, this guy felt comfortable enough to prop up his holster and pull out his sword as the ball flies towards him. It worked out, as he managed to slice the ball perfectly. The most impressive part? The ball came flying at him out of a hidden pitching machine and not via a real pitcher, meaning he had no way of accurately knowing when it was going to shoot towards him.
This is one of those videos that should make more sense the more you watch it, but somehow, it only becomes more inexplicable.