It was probably made in the 80's or 90's and it's set a couple of centuries back in Japan I think. It's about a boy whose village I think was attacked and I believe he fled. Then somehow he found out that if he dug up the ground under some arch at a specific time he would find something valuable. He did that once and found wealth and became very rich, but I think it all disappeared somehow. He also did it a second time and found an armor that could talk and when he wore it it would fight his battles for him, so he became very powerful. But he lost that as well. The third time he was under the arch an old wizard or some-such came and took him. They were flying to the skies and I think he told the kid he has to be quiet and not say a word or something bad would happen...