During the time where the Japanese have invaded and conquered Asia, they have also looted their national treasures and these includes gold, silver, precious stones and jewelries, golden Buddhas, and etc... from different countries in Asia (Malaysia, India, Thailand, Burma, Singapore, Java, etc...) The Japanese ships their looted treasure back to Japan for financing their Military supplies and food rations. However, the Japanese has suddenly stopped shipping these looted treasures back to their home country when American Naval vessels have been deliberately patrolling the sea areas and also a strategy to cut off incoming or outgoing supplies. In that situation, the Japanese had been alarmed to cease and change their strategy preventing the risk of losing their stolen war loots.
The Japanese Officials then decided to transfer the treasures to the Philippines ,as they have considered the established military bases and a perfect strategic location around the archipelago of the Philippine Islands. But the Japanese were unexpectedly defeated by the Americans by dropping 2 Nuclear bombs at Hiroshima and Nagasaki where there food and military supplies where. Thereby surrendering when they had ran out of rations and ammo. That is also the reason why they do "Kamikaze" or sacrifice their self for their honor ( similar to what suicide bombers do in the middle eastern countries). Specially Japanese Aircraft pilot run out of bullets they use their aircraft and attacking American naval ships by colliding with them.
Their plan failed and took their treasure to various parts of the Island and buried them in the most secret way as possible. The treasures where buried deep at about a 100 feet, others where tunneled underground, and others buried their treasures near water sources. They also took their treasures on the mountainous part and northern part of the Island and buried them on the roads and under the trees leaving codes and signs as they where running from the Americans during their attack. Maps were drawn indicating sites and special instruction were written in "Kanji" which is really very complicated to read.
Diggers or their workers were the POW's (Prisoner of War) and come from different parts of Asia. As I recall from the stories from the person who have witnessed the horrific war, some were Chinese, Burmese, Filipino, Java, Americans, Vietnamese, Singaporeans, and etc... Even women and children were abused and used as a digger and later after the looted treasures were buried and secured they execute POW's and even their own soldiers to serve as guardians to the treasures and as well as to protect their secret location.
They also secure booby traps on the treasure such as bombs, water traps, and poison or poison gas to prevent their enemies from obtaining their treasure. Until now, these booby traps are still active and should be avoided as possible and should not be dealt with. I have heard a lot of stories that have died because of unexpected explosions and being poisoned because they are not being careful and ignorant.
Japanese today including Koreans are coming to the Island to recover treasures of their ancestors. A lot were seen digging using heavy equipment's and as well as they were being backed by government officials. Many are still not recovered to this day and in rare cases there were lucky ones whom have found treasures accidentally.