If you’re worried about greedy relatives stealing your money, the Shocker ATM Bank should cure the problem. When you put money in it, it will yell “Eeeeee!” for some reason. I guess it’s happy for you and your financial situation. The bank will also know the difference between all coins between 1 and 500 Yen, and will display the total amount saved so you don’t have to count it yourself.
Comes with a security card and an individual pin number. It will cost you $30, but it will cost your family several nasty shocks before they learn to keep their mitts off. It also has alarm clock and calculator functions. Hands off my yen mofo!