The waterfall technique is a small exercise to relax your mind when you feel stressed.
A Shinobi need for mental peace when he must carry on own missions.
After I explained the mind shield technique, a Ninja must have a clear mind in order to proceed in daily life without stress.
This exercise is really simple, close your eyes, uphold elbows on the table and cover your eyes with palms hands.
Right palm hand for the right eye and left palm hand for the left eye, relax yourself and breath slowly.
Visualize a waterfall is flowing in your mind and your thoughts fall downstream.
Keep this position for a couple of minutes, visualizing this waterfall, which reverses a great amount of water with your thoughts and concerns.
With this technique, you can clear your mind about negative thoughts and find again a sense of peace.