Hasta uttanasana or raised arm pose is a great pose to stretch and tone the muscles of abdomen and arms. It helps to remove unwanted belly fat and achieve a flat stomach. Learn and practice Hasta Uttanasana @ https://www.youtube.com/watch?v=kQuRvneuIYg You may also refer https://www.youtube.com/watch?v=OkeXtEV_0ks for developing a complete plan for flat abs.
Hasta uttasana pose, otherwise known as the Hand raising pose is one of the most effective asanas that help you achieve flat abs if done regularly. This intense stretching pose tones your abdominal muscles and also improves the digestion.