I'm a Corpse Buried Under a Cherry Tree, but the Tree Got Cut Down

You know how they say, "There are corpses buried under cherry trees"?

As a proposition, that might actually be true. After all, if you go back far enough, there’s probably some kind of corpse buried under almost any patch of ground.

So, hello there. I’m the corpse under the cherry tree.

To introduce myself as a corpse: I was buried under a cherry tree used as a roadside tree in a certain town during the post-war reconstruction period. Well, things happened in the black market, I was buried to dispose of the body, and a cherry tree was planted on top of me.

I’m just a humble set of skeletal remains.

But that cherry tree was recently cut down.

You see it often lately—roadside cherry trees being felled.

People say all sorts of things, but to put it simply, the trees have reached the end of their lifespan. Old cherry trees often rot from the inside and become hollow, making them dangerous if they break. It’s unavoidable.

In fact, the tree above me had a trunk that was completely hollowed out with mushrooms growing on it. I was thinking, "Ah, this tree will die eventually," and then—bam—it was cut down.

So, the "corpse under the cherry tree" became the "corpse under the cherry stump."

Oh, you might wonder how a corpse knows what's happening around it? I'll explain. I just know. I’ve been the corpse under this tree for 80 years, after all. I’ve developed various "corpse skills." The hint is bone conduction.

Anyway, as I mentioned, the stump above me is rotten in the center, so it’s shaped like a donut—there's a hole. Or maybe it's more like a baumkuchen?

I don't know if it's the shape of that hole or what, but it seems to stimulate a human's "urge to put things inside." People keep dropping all sorts of things in there.

Empty cans, plastic bottles... I thought it was a nuisance at first. But then, one day, a child's toy shovel fell in. You know the type—the kind kids use in sandboxes. It was shaped like a giraffe.

I think a child put it there, maybe just to see what would happen or by accident. Regardless, a shovel fell down to where I am.

At that moment, I thought, "This is it!"

Since then, I’ve been secretly digging a hole with that shovel. As for the dirt I dug up? There happened to be a cracked, thick sewer pipe near where I’m buried, so I skillfully dumped it in there or scattered it bit by bit on the surface. I did it very slowly so as not to cause a clog. A clog would be a big problem, after all.

When it rained heavily, the dirt I dumped in the sewer would wash away, so I’d dig a little further. I have nothing else to do, so I work steadily. I’ve got the backbone for it—literally.

By digging and digging like that, I managed to create a small basement. It’s quite cramped since it’s underground, but it’s about the size of a two-tatami room.

After that, I got creative with my living situation. First, I lined the floor with stones I found while digging. It’s just a gravel floor, but adding a touch of human-like intent made the space feel a bit more comfortable.

Then, I started making tools. First, the empty cans that fell from above. I crushed and deformed an aluminum can with a stone to create a rudimentary blade. Then I took a steel can—steel is harder, but if you combine it with a stone and work it right, you can cut it—and flattened it out like a sheet of iron.

Using that iron sheet and the clay I found while digging, I built a small furnace.

Since empty cans keep falling from above, I can manage. I gathered dried tree roots and tissues that fell from above, put them in the furnace, and lit a fire.

I was so moved the first time I lit it. The surroundings suddenly brightened up. Since there isn't much to burn, keeping the fire going is a constant struggle, but it gave me motivation.

And you know what I wanted to do with that fire? Upgrade the giraffe shovel. I took the plastic bottles that fell from above, cut them up, and placed them on an iron sheet from a can that I’d cut into a shovel shape. I placed the giraffe shovel on top and fitted a rolled iron sheet into the handle. Then I heated it.

As planned, the plastic melted and fused everything together, completing a powered-up shovel. This is what I wanted. It made the digging work much easier.

Using the same logic, I combined plastic and iron sheets to make a simple knife. Of course, it sounds quick when I write it down, but it was a slow, steady process. Bone-dry humor, right?

With the ability to dig further, I reached the stump of the neighboring roadside tree. This allowed me to secure dead roots for fuel. Reaching other trees also meant I could get twice as many discarded items.

And most importantly: companions. There was a corpse buried under the neighboring cherry tree too. Now I have a partner, doubling our manpower. Every time we dig further, our numbers grow.

Once things started moving faster, I decided to build a tank. A gas tank. This was truly difficult. Essentially, I had to form it by combining iron sheets and sealing them with plastic. Since it’s a gas tank, there can’t be any holes. I submerged it in water and blew air in—I used plastic bags since I don't have lungs—and if bubbles came out, I’d seal the hole. That was the process.

Anyway, I made a leak-proof tank and attached a pipe made from cans.

What I wanted was a biogas system. I haven't mentioned it yet, but among the things that fall from above, there’s quite a bit of dog poop. I used to dry it for fuel, but now I’ve made it so I can use methane fermentation to create flammable gas.

Of course, it would be faster to poke a hole in a city gas pipe, but a gas leak would definitely be detected. They’re strict about that. So I avoided it.

That’s how I secured a supply of gas fuel. The hardest part was the valve. At first, I could only make a very primitive one because I didn't have screws. I was really lucky to find some old plumbing parts while digging. That allowed for a major upgrade.

Next was upgrading the furnace. Since the fuel efficiency was much better, I improved the furnace too. I became able to melt not just plastic, but aluminum. Do you know the melting point of aluminum? It’s 660 degrees Celsius.

With this, I could make ingots from aluminum cans. The first thing I made was a hammer. I made a mold out of clay and poured the metal in. I also wanted an anvil, so I patiently hammered an ingot into a flat plate and laid it on concrete to use as one.

With the furnace, I could make two more things: bricks and cement.

As for concrete, it’s relatively simple. If you heat concrete, the calcium hydroxide dehydrates and turns back into calcium oxide. By removing the gravel, you get cement, even if it’s poor quality.

For bricks, if you fire mud bricks made from dried clay, their strength and heat resistance increase.

By combining these materials, I finally—finally—reached a fairly advanced furnace. Now I can process iron.

Things got much better once I could process iron. The strength of the things I could make increased significantly. From there, it was just constant equipment upgrades. The biogas device too. I turned it into a system that extracts methane raw materials from the sewer pipes for fermentation, and then I built a device to remove carbon dioxide from the generated gas to increase purity and combustion efficiency.

Oh, and of course, as you might have guessed, there’s a way to get iron from aluminum and iron oxide via a thermite reaction. But aluminum is precious in its own right, and I needed a lot of iron, so I decided against that route.

Also, I needed adhesive. I’m sorry to say I had to sacrifice some mice. I caught mice coming in from the sewers with traps and boiled them to make animal glue. If used correctly, animal glue has decent strength.

The mice were also useful for their hides. I collected the skins and glued them together to make bellows. You see, I don't have lungs, and plastic bags had their limits.

Next, I moved on to glass processing. It’s very hard to extract silica sand from soil, but since bottles fall from above, I crushed them and built a glass furnace.

What I wanted to do was make a distillation apparatus. It was a huge struggle to make the ground glass joints common in lab equipment, but being able to attach and detach parts is a big advantage. I also made bottles with a certain degree of airtightness.

With the distillation apparatus, I made wood vinegar from tree roots. Distilling wood vinegar yields acetic acid and ethanol. Also, I collected the sweet dregs from discarded drinks, fermented them, and distilled them to get ethanol. By burning PVC and passing the gas through water, I obtained hydrochloric acid through distillation.

And experimentally, do you know what "fatbergs" in sewers are? Simply put, they are congealed masses of sewer oil. I collected these as fats and oils and successfully produced biodiesel by performing transesterification with methanol and hydrochloric acid. I can't build a diesel engine yet, so it’s just a small amount of high-quality fuel for now.

But I’m thinking of an engine eventually. I’ll definitely have to build a generator someday.

Then there’s fiber. Fiber sources are very scarce. I stretch PET resin from plastic bottles into threads and twist them together. This is an extremely labor-intensive task. To make it efficient, I want to create a nozzle that can continuously heat the resin and automate the spinning, but that’s a challenge for the future.

Speaking of future challenges, there’s the stable production of sulfuric acid. The sewer and methane fermentation systems produce hydrogen sulfide as a byproduct, but the concentration is too low to easily turn into sulfuric acid. So I want to extract it from gypsum. If I can find discarded drywall—gypsum, or calcium sulfate—I can get sulfuric acid gas through thermal decomposition, leading to stable production.

However, I haven't been able to dig up a significant amount of drywall from the soil yet. I’m sure it’s buried somewhere as illegal dumping. I just have to be patient until I find a "vein."

Finally, the biggest problems are rubber and solvents. Having rubber and solvents would solve so many issues.

I want to make synthetic rubber someday, but the hurdle is quite high. I’m thinking of digging close to the surface to get asphalt and cracking the petroleum components in it, but if I take too much asphalt, I’ll be caught, and I’d have to separate the products. It requires scale.

This is the biggest obstacle right now.

It really comes down to oil, doesn't it?

Come to think of it, I’m a person from the post-war era, and war was always about oil too.

That’s what I think about, but one day, I will build a secret underground empire!