Holding the nigiri-game helps you develop a firm grip. Lifting the nigiri-game towards the front and sides strengthens your shoulders and wrists. Lifting the nigiri-game towards the back helps develop your forearm muscles and improve your posture.Extend your toes and maintain your soles and toes firmly in contact with the floor as if they were stuck to it (like the roots of a willow spreading below the soil). Turn your knees inwards and tighten your thigh muscles. Training with the nigiri-game develops your stability, as well as strong hips, legs and feet.Training with the nigiri-game strengthens the internal organs using the deep-breathing system. It also helps develop a strong lower abdomen area.First of all, use an empty nigiri-game for training purposes. After a certain time, make it gradually heavier and heavier by adding sand. Add more sand as your physical strength improves. After you have developed a certain grip strength, use a nigiri-game with a straight nozzle. After you have even more gripping power, coat the nozzles of the jars with oil to make them more slippery. In order to increase your grip strength for the nigiri-game, practice holding tennis balls or small pebbles.