It's a technique that makes you play 4 consecutive notes but make you hear 3 consecutive notes. I still remember being so surprised when I first found out. I hope you will have good results by repeatedly training at a slow speed. For your information, I hope you learn through the video below. When purchasing the score, all the contents of the video below are recorded, so please purchase it and learn.  

  Please learn through the video below.
  If you purchase it, all the contents of the video below are recorded.