Japanese treasures are burried with water trap, sand trap, vialled chemicals, chemicals in drum, century bomb string activated and other deadly items. If a hunter does not have any valid treasure map from who burried it, it is almost near to impossible to get the treasure. these map are written in kanji, an old japanese language and dechipering it is not easy. I have once a book that have most of the symbols written in japanese characters, but its validity is uncertain to me. As I understand treasures with this kind of traps are big volume, say not less than 5 tons and more. In my experience, water trap comes within 12 to 18 feet, and once it is opened the flow of water is almost unstoppable. The in rush of water and its volume is more than enough to barred the hole.