Batteries... We use them so often that we hardly even think about it. Mobile phones, cameras, portable audio players - even your car keys might have a battery inside. Japan makes 4.8 billion batteries every year, and the Japanese have a long history of battery breakthroughs, from recent advances in rechargeable batteries to what may have been the world's first dry-cell battery over 120 years ago. Recently, electric car batteries have been used not just for driving, but as power sources for entire homes. After the Great East Japan Earthquake in March 2011, supplies of water and electricity were cut off in many parts of northeastern Japan. Batteries played a key role in helping evacuees. On this edition of BEGIN Japanology, our theme is batteries. We'll see how these small sources of power, invented in this small island nation, have transformed the lives of its people.