When it comes to tunnels, the JIA (Japanese Imperial Army) did quite an interesting job building them. They are quite complex that some of them still remain until today. One among them is the one which can be found at Tukon Hills, Batanes known as “Dipnaysupuan Japanese Tunnel”.

As a treasure hunter, what I noticed about these Japanese tunnels is that they are not always built in the same exact manner. The reason why is probably due to the type or properties of the ground. 

So if the place consists of a ground that has soil and loose type of soil then it has a huge tendency to collapse so the Japanese soldiers utilized timbers and rocks for support. But if the soil is hard then they did not need to put supports. 

Size of the Passageway

When the Japanese soldiers built their tunnels, they did not actually observe sizes or spaces of the passageways. So in all of the tunnels that I came across, there are tunnels with spacious passages where you can literally stand and walk around comfortably.

On the other hand, there are also passages that are too tight that in order for you to pass through, you need to crouch and slowly move your way.

Chambers or Rooms

Japanese tunnels always consist of chambers or rooms which tend to be more spacious to fit a certain group of individuals. It is also very common that they made not just one room but multiple rooms to accommodate the space they need.

They used these rooms to gather around, plan their military actions, and rest or sleep.

If you are working on a certain Japanese made tunnel, always expect that there will be more than one room or chamber. But through the help of the markers around the tunnel and being able to interpret them correctly, you should be able to locate the chamber where the item has been stored.

In most cases, the chamber is often sealed with very hard and thick concrete which makes it too obvious that something is hidden behind it. By breaking through the seal, you can expect to uncover the treasures.

However, it is not always the case that the chamber with the treasure deposit is sealed with concrete. There are some situations where the chamber is not sealed at all where the items are simply buried underneath it. But the problem is that there are several rooms around the tunnel which means, you need to locate the correct chamber to dig.

In addition to this issue is when you do not know how to interpret the signs around that could lead you into the designated room. But not unless you are a hard worker where you can dig every chamber or room of the tunnel.

Japanese Tunnels as Defensive Strategy

You might be surprised to know that the Japanese tunnels were not just meant as places for hiding the Yamashita treasures. It was also intended as a defensive strategy by the JIA against the Allied Forces.

Many of the Allied Forces had actually been taken down by the Japanese soldiers through the use of their tunnels. They did it in a way by suddenly popping out from their holes and surprising the Allied Forces with their ambush attacks. Clever isn’t it?

Anyway, you have to know that one of the main reasons why the JIA lost against the Allied Forces was due to the lack of their supplies. They no longer had food so as bullets to fight back. So even if they have a good strategy, it was rendered useless because they had nothing to use.

Treasure Deposits at the Tunnel Entrance

It is always a common perception for most treasure hunters to think that the treasure deposit is hidden inside the tunnel. However, this is not always the case because some of the Japanese soldiers had already anticipated this to happen.

So instead of hiding their treasures inside the tunnel, they hid it outside. And based on my experiences, they commonly buried them near the entrance of the tunnel. Anyway, markers are always what dictates the location and confirms the treasure deposit spot.

Treasure Deposits in Tunnel Passages

If the treasure deposit is not hidden inside a certain chamber or outside the tunnel, it is also possible that the deposit is hidden at a certain portion of the tunnel’s passageways. Interpreting tunnel passages for treasure deposits is completely similar to the old creeks, rivers, and trails that have already been discussed in the previous posts.

By studying the shape of the passageway of the tunnel on your site, you should be able to determine its shape. So in this case, if it has a shape similar to a letter “T” then the treasure deposit can be found at the intersection portion indicated by the dot symbol in this illustration. 

If the passageway bears a curve shape then the treasure deposit can be found at the outer portion of the curve. Again, refer to the dot symbol in this illustration for the location of the item.

If the passageway bears the shape of an X or Cross then the item is buried at the center spot where the four passages intersect together.

Image: Y shape

And finally, the most common shape is a passage similar to the shape of the letter Y. By referring to this illustration, the dot symbol represents the treasure deposit which means that the item is at the side portion where the three passages had intersected.