As predicted, it hadn’t taken Shoko-san long to fetch Paul’s music player and bluetooth speakers. He’d had long enough for a brief picnic lunch with Inari, although it felt a bit constrained given that the two Oni sisters had taken it upon themselves to act as bodyguards, standing back to back, either side of them, diligently watching the surrounding forest.

Paul wasn’t entirely sure what they thought they were guarding against, but being above ground clearly made them nervous and this way they had something else to focus on, other than their own feelings of anxiety.

Shoko-san arrived breathless with the media player and bluetooth speakers in hand. Inari tilted her head as she looked at them.

“What are those?”

“Music player and speakers. Oh, yeah, you probably haven’t seen them before.”

“No I haven’t, how is playing music going to help you?”

Paul turned them on, and handed a speaker each to Yuri and Yuko.

“Ok, it works like this, this thing I’m holding is the music player...”

Paul turned it on, waited a moment for it to sync and then pressed play. The first bars of Moonlight Sonata drifted out of the speakers, startling both the Oni and Inari: Shoko started to hum along.

“..you see it sends the sound to the speakers using a radio signal essentially. Point is, we already know that magic interferes with radio signals, so I figured by using this and listening for how badly the speakers crackle, I can work out how far away the source lies. Also, since these are fairly cheap and nasty speakers, and only work well if the internal antenna is pointing the right way… ah.. Yuko, could you slowly turn round in a circle? Yes like that, thanks.”

As the tall green-eyed Oni girl turned on the spot, the music coming from the speaker she was holding faded, crackling more, and then as she revolved back to original position it came back to full strength.

“I think I can use them to triangulate the source of the interference, ie, in what direction the source of the magic lies. Just rotate it until the interference is really bad, then draw a line pointing in that direction. Do that with both, and where those lines cross is where it is. Well, in theory. I don’t know how well it’ll work in practice. There could be any number of reasons why it won’t work, but it’s best I’ve got…. Um, Yuko, you can stop now. Thank you.”

Inari slowly nodded.

“Ah, yes… there are spells that work like this, although I have not seen one that could do more than tell you that the source of power was somewhere on or under the mountain. But using two such devices, so that one can, triangulate you called it? That is clever!”

Paul ducked his head slightly.

“Not my idea. This is how the Germans used to track down radios operated by the French Resistance during World War Two. They’d have pairs of radio trucks driving around, intercepting the signals and logging direction and strength, in a sort of cat & mouse game. I ran across it as I was researching something else and thought it interesting, but never did get around to using it in a story.”

“You have an amazing breadth of knowledge Paul-san.”

“Ha! More like a mind stuffed full of odds and ends of useless bits of information.”

“Not that useless my Herald.”

“Only if it works, Inari-sama.”

Inari shook her head slowly…

“You are determined to think little of yourself Paul-san.”

“I prefer to think of it as keeping my feet on the ground, a bit at least. Which given just how fantastical a turn my life seems to have taken, is probably a good idea. Otherwise I’d be thoroughly lost.”

“Well, as you wish my Herald, perhaps you are right and it is better this way. Too much praise is as bad for one as too little.”

“I guess a Goddess would know about that. Occupational hazard when you’re worshipped and idolised, literally, by the masses, right?”

Inari laughed, nodding, a definite twinkle in her eyes.

“Well said, well said indeed, and very true. When I think of some of the other Divine beings and their inflated egos. Of course, it’s never a problem I had!”

Paul gravely nodded agreement.

“Oh, of course not Inari-sama. You are, of course, the model of feminine perfection, a veritable paragon of modest maidenly virtue.”

They managed to hold each others gaze for perhaps a breath or two, before the dam broke and laughter spilled forth. Inari doubled over, filling the air with musical laughter as Paul’s belly laugh rumbled a bass line to it.

Yuko and Yuri exchanged a look, as if to say; ‘this is how a goddess behaves?!’ and went to stand over by the mine entrance. Shoko fell off the log she’d been sitting on, adding her own indecorous snorting giggle to the merriment.

Paul was still in high spirits an hour later, despite the search being slow going. Ideally he would’ve liked to have modelled the mine and cavern system in 3D on his laptop, so he could get a proper idea of spatial relationships. As it was, he was making do with a pack of coloured pencils, evidently swiped from a restaurant, and a clipboard with multiple layers of thin tissue paper.

He wasn’t sure how an area of high magical energy would affect a computer chip, and had no intention of finding out using his only means of making a livelihood at present.

So they were tediously working their way around the map in a spiral search pattern, marking the direction and strength of the signal interference, and physically plotting out the source of it, layer by layer.

After awhile Paul called a halt, sitting down on a bolder to try to figure out what he was looking at. The two sisters exchanged some quiet words, and Yuko went off while Yuri stayed behind, guarding the abstracted Paul.

After perhaps half an hour, Yuko returned, carrying a basket containing three bento boxes. She handed Yuri one, and took one for herself, before tapping Paul on a shoulder and handing him the third. Paul didn’t look up from where he was scribbling calculations and doodling what looked like abstract blobs in the margins.

The two sisters sat, eating for awhile, as Paul took the occasional bite of his food. Eventually he looked up, and noticed the food.

“Oh… thanks. I hadn’t realised it had gotten so late.”

Yuri smiled slightly, just enough so her bottom tusks showed.

“It’s ok… you have a lot on your mind. Or you seem to. I can’t make out what you’re doing.”

“Tell the truth, I can’t either. I’m fairly sure the source is on the lowest level , just above where it’s flooded thankfully, but I can’t pin down exactly where it is. It doesn’t seem to have a point source but it’s spread out. I think.”

Absently he twirled one of his chopsticks between his fingers. It slipped out of his grasp and fell with clatter onto the clipboard. Paul swore slightly, then went to pick it up, only to stop and stare. He nudged the chopstick with a finger tip... and froze.

“Bloody… Hell! Why didn’t I see that before!”

“Paul-sama?”

“Oh nothing, just I’m an idiot! I’ve been assuming it’s either an area effect or a point source, but the numbers don’t add up for either of those, because it’s a god-damned LINE!”

“Uhh...”

“The source of the magic isn’t a single something, or patch of something, it’s shaped like a line... No, well, yes… It’s more like a curtain in 3D, running diagonally across the map, starting at the lowest navigable level and extending downwards like a.. a… well I don’t know what like, but it’s sort of shaped like a flat sheet embedded in the rock edge upwards. If that makes sense.”

“Oh! I think I see. So now what?”

“Well, now I know where it is, lets go see what it is. There’s a passage way that if this map can be trusted, runs though the thing, right... about… here! Ok, we’re going there.”

Paul stabbed at the stack of tissue paper with one of the pencils, making an X to mark the spot on the map. Then for good measure drew a line across the map.

“Ok.. so, we need to head that way and take the second right, yes?”

“That is correct Paul-sama.”

“Well, got that much right. Yuri, lead on!”

“Perhaps you should finish your bento first?”

“Oh? Ah.. yeah. Thank you Yuko for fetching it.”

Paul to his recollection hadn’t heard the green-eyed Oni speak before, but as her cheeks went pink and she ducked her head, she just about audibly murmured.

“My pleasure Paul-sama.”

After an hours walking, scrambling, and certain amount of wriggling to get though some tight spots, they found themselves in a small rocky tunnel, barely wide enough to edge though sideways. Yuri and Yuko in particular suffered, and had to shed their armour some distance back. As it was, they were still only able to breath in shallowly, as certain prominent parts of their anatomy were rather compressed by the narrow confines. Paul had offered to go on alone, but they refused to leave his side.

Paul studied the rock face inches away from the tip of his nose.

“Huh?! It’s a fault line!”

“What?”

“The crack here, see the way the banding in the rock strata don’t quite line up either side? It must run all the way down off the bottom of the map, and across it diagonally. Hence the sheet like shape. But why on, or rather in, earth would a fault line be the source of magic?”

“Maybe it’s something in it? I can hear water trickling in there, perhaps it carried something down?”

Paul glanced sideways at Yuri and nodded.

“Good suggestion, perhaps...”

Paul took out the small miners geological hammer he’d found earlier, and picked away at the rock.

“Hmm, granite. These little blue crystals I think are tourmaline. This black stuff looks like haematite maybe.”

Paul bent his head and licked the rock.

“Yup, haematite. Tastes like iron. That’s to be expected. There’s probably a heavy deposit of the stuff somewhere and the water is dissolving it and then it recrystallises here. Hang on. Turn the lamps off will you please.”

The sisters exchanged a look over Paul’s head, and then turned off the lamps. Paul shut his eyes as darkness descended, allowing them to adapt quicker, and then using his finger tips to find the crack, leaned in closer and peered into the hand-span wide gap, trying to see what he thought he’d glimpsed.

“Aha! I thought I saw something… dammit! If I can just get my fingers in...yes!”

He pulled out a tiny fragment of crystal, that in the absolute blackness of the cave glowed like a green-blue star in the night sky.

“Now what the heck are you I wonder?”

“Paul-sama, what have you found?”

“No idea Yuko, but whatever it is, it’s glowing and that’s odd enough it could be something.”

“It’s glowing? I see nothing. Do you Yuri?”

“No sister, I don’t.”

Paul rather futilely glanced to either side.

“You don’t? But it’s right here in my hand. How can you not… unless… Oh! Huh, maybe that’s what she meant?”

“Paul-sama?”

“Oh, something Inari said. She said I had an open third eye, and was one who saw things unseen. I thought she was being poetic and meant spirits and stuff. But now I think she might have meant it literally. Whatever this crystal is, maybe what I am seeing from it isn’t light, but raw magical energy. My brain is interpreting it as visual stimuli, or perhaps because I’m sensing it with something in my retina or visual cortex. I dunno, but it’s not any part of the electromagnetic spectrum I think.”

“I... don’t know what any of that means. Can we light the lanterns again please?”

“Huh, oh sure, yes!”

Paul blinked as the tunnel was flooded with what to his eyes was brilliant light. He glanced down at the fragment he’d pulled out of the ground, and saw that it was a tiny chip of clear crystal with a bit of haematite adhering to it.

“Interesting, it looks like quartz, but why? Ok, I think I need some more samples of this stuff. You two back out of here to where it gets wider, while I’ll stay in here for a bit longer and collect a few more rocks. I’ve got my penlight, that’ll be enough to see by with. I should only be a few minutes, so don’t worry. I’ll shout if I need help.”

The tall Oni were visibly concerned, but nodded their agreement, poorly hiding their relief to leave the rocky coffin-like confines.

After ten minutes chipping away at the rock-face in near total darkness, Paul felt he had a small bag full of what to his eyes, was softly glowing crystals. Although he did notice as he handled them that they illuminated nothing and their ‘light’ cast no shadows. He was chipping off one last larger bit, when it happened. The crystal spar snapped off, leaving behind the haematite base with it’s tourmaline inclusions, and the eerie non-light went out immediately.

Paul grunted in surprise. Puzzled, he looked around and finding another needle-like spark of non-light, carefully and deliberately snapped it off it’s base. The tiny spark went out again. Paul paused thinking. Each of the glowing crystals he’d collected had one or more bits of black shiny iron ore attached to them. Some, roughly half, had blue tourmaline crystals as inclusions either to the clear crystal, or to the base.

He opened the bag and rummaged though it, and frowned in the darkness. He could feel all of the samples, but some where already ‘dead’ and several were visibly dimming even as he watched. He clicked on his penlight torch and inspected them. The ones that didn’t have any specks of blue crystal were already dead or dying; the rest seemed ok, glimmering like moonlight seen through deep water.

Paul frowned down at the handful of sharp edged gravel thoughtfully. Something about the combination of all three was necessary. Isolate just the clear crystal, which he was almost certain was quartz, and it died immediately. Add the haematite and it ‘lived’ a short while but died not long after being separated from the rock face. All three and it seemed to keep going, at least so far.

Putting the handful of samples away again, he started to make his way back up the passage crab-like, until he reached where it widened and he could walk normally. He was silent as he rejoined the Oni sisters, frowning deep in thought.

By the time the small party reached the Oni’s Great Hall, Paul had been silently lost in thought for twenty minutes roughly. Yuri and Yuko had guided him past obstacles but had refrained from speaking to him.

Tatsuo caught sight of them and came over.

“Hoi! Paul-sama.. did you find what you were looking for?”

Paul replied automatically, in a distant, distracted tone.

“I found something… not sure what.”

He carried on walking past Tatsuo, who looked at him puzzled, then turning looked at the two Oni girls.

“Is he ok? You didn’t let him hit his head did you?”

“No Tatsuo-dono! He is thinking, very hard. I think.”

Paul stopped at a blank wall, made of black iron ore. Patting down his pockets he found a piece of chalk, and started to write. The three Oni came up behind him silently, watching as Paul filled in notes in a mix of English, Japanese and what seemed to be several European languages. There didn’t seem to be any logic to the way he changed languages, sometimes switching mid sentence.

The notes themselves were jumbled, sentences wandering off, being joined to other ones with long arrows or just colliding as Paul wrote. As a small crowd gathered, Paul sketched in strange pictures, geometric shapes made up of sticks joining circles with one or two letters in them.

Without looking up from what he was doing, Paul pointed off to his left at Yuri.

“Hey you, go ask Shoko if she can find me a car battery and some jumper cables. Also I need some salt and a reel of copper cable from the workshop.”

“Ah! Yes, Paul-sama!”

“Someone tell me how often you get earthquakes here please?”

Tatsuo blinked, and looking round realised everyone was waiting for him to speak.

“Ah… one or two every few months.”

“More specific please.”

“Ummm… I would say… one every six to eight weeks, but only very small ones. One big enough to really feel perhaps once year.”

“Uh-huh. About what I thought. I’d have to ask Inari about the frequency and magnitude longer ago.”

“Ahh... Paul-sama what are...”

“Shh!”

“But...”

“SHUSH! I’m thinking!”

“Paul-sama perhaps...”

Without looking Paul’s arm shot out, and with an almost audible z-z-zip sound a piece of chalk shot unerringly towards Tatsuo, impacting in the precise centre of his forehead and exploding in a small puff of chalk dust. The Oni staggered back several paces. Mostly out of surprise.

“One more interruption and it’ll be detention for you.”

Tatsuo blinked, and then whispered to Yuko.

“Paul-sama was a teacher once?!”

Yuko shrugged, at a loss, and whispered back.

“Perhaps. I wouldn’t want to be in his class.”

Tatsuo nodded slowly.

At that moment Yuri arrived, panting, carrying the items Paul had asked for.

“Paul-sama.”

She stopped as the other frantically made shushing motions to her. Yuri looked at them bewildered, wondering why Tatsuo was wearing a dot of white face make-up.

Silently she placed the car battery and other items on a nearby table, and waited. Paul noticed them and, taking the sample bag out of his pocket, set to work. Taking out a pocket knife he measured several arms lengths of wire and cut it off, stripping the insulation from the ends. He fashioned a coil, and then carefully inserted the bare ends of the wire into the aux socket of one of the speakers.

Switching it on, it made a loud humming sound. He picked up one the crystals, and placed it in a bowl of water to which he added a pinch of salt and some of the black rocks. Paul waved the bowl through the coil. The humming from the speaker grew louder and fainter again as the crystal in the bowl moved through the coil of wire.

“Aha! How’d you like that Faraday! Induction without a magnetic field! Ok… lets see..”

Paul spread the samples out on the table and picked one of the ones with a large blue crystal that was partly growing through the side of the clear crystal. Paul laid the wire coil flat on the rock table, and looked around.

“Hey you, big chappie. Come here.”

The bulky Oni, looking visibly alarmed looked at his lord for support and guidance. Tatsuo shrugged, and nodded in Paul’s direction. With faltering steps the muscular Oni stepped forward.

“Ok, that club thing you’re carrying, it’s bronze right?”

“Yes Lord, it’s been passed down in my family for...”

“Good, never mind the history. It’s non-magnetic that’s what’s important. Ok, I want you to carefully place the end of it on that blue crystal, and when I tell you to, I want you to push down on it as hard as you can. Really lean into it. Got it?”

“Umm.. yes, Lord.”

With some trepidation the Oni put the butt end of the maul onto the blue crystal, and waited as Paul carefully checked the connection of the copper coil. The other Oni exchanged a number of looks, and then slowly began edging backwards, which did not do wonders for the nerves of the ‘volunteer’.

“Ok, set... annnnd... NOW!”

Squeezing his eyes shut, and mentally saying a prayer to whatever gods were listening, the large Oni pushed down hard, leaning into it as instructed.

The speaker produced an ear splitting squealing sound, and with a bang expired in a cloud of black, foul smelling smoke. Several nearby plates and drinking bowls levitated off the table and away at considerable velocity.

The Oni flew backwards, as if he’d stuck his fingers into a live electrical socket. He collapsed against the wall, still convulsively holding onto the bronze maul, which was now glowing a faint shimmering green colour.

“Eureka! It works! And wow, that was some power output!”

Tatsuo gripped Paul by the shoulder, dragging him round to face him.

“Paul-sama! I have tolerated your… strangeness, but you WILL explain yourself!”

“Huh? Oh, ok... I figured it out. I know how magic is made now!”

“What?”

“Alright. You see it’s like this, those are tourmaline crystals, blue tourmaline. They are strongly piezoelectric and paramagnetic which means that under enough pressure they create a strong EM field, like, if it was inside an earthquake fault line. Now ordinarily that’s not a big deal, but add some conducting electrolyte for the contact and some of what I think might be quartz with haematite inclusions, and you’ve got something that will turn pressure into electricity and that into raw magical energy. I think the haematite acts as a magnetic ‘battery’ storing the energy as a magnetic field, maybe. I... don’t know how that last step works but it seems to violate the law of conservation, so it might be that magical energy is some sort of fifth order spatial construct perhaps, or a fold in the p-membrane and…”

Tatsuo slowly let go of Paul’s shoulder… shaking his head in bewildered confusion.

“I... did not understand one word of that. Could you refrain from blowing up my people at least, please?”

“What?! Oh. Aha. Yes. Sorry about that. Sometimes I get carried away. Umm… I threw chalk at you, didn’t I?”

“Yes Paul-sama. There was also talk of detention?”

“Yeahhh… I taught ESL, ah, English as a Second Language, for a number of years as I worked my way around Europe. It kinda left some habits.”

“I see.

Paul looked around at the crowd of Oni, who were looking back at him with varying degrees of fear and awe, from a safe distance… and in some cases, from behind things.

“Ohh, boy. I’m really sorry Tatsuo. I... get kind of manic, sometimes, when an idea really gets hold of me. I develop a really bad case of tunnel vision then.”

“Yes. I see that now.”

Paul hung his head.

“I apologise profoundly. Please forgive this foolish one.”

“Paul-sama, if you have truly unlocked a mystery that has eluded even the wisest of sages and magicians for centuries… then you have nothing that needs forgiveness.”

Looking up Paul grinned boyishly.

“Yeah. I think I have. Wow! I really, really did it! Now all I have to do is figure out how to to replicate that process in controlled, and safe, manner.”

“Outside, please.”

“Um, yeah… there’s a workshop… um. If I need more rocks can someone...”

“We will supply you. Yuko and Yuri know what you need.”

“Ok. Oh.. actually, better if they showed someone else where to get it. Someone skinny. It’s a bit of tight fit and those girls are… umm, well, they’re kind of the wrong shape, in places, for that job.”

Tatsuo’s stern expression almost cracked, but only almost.

“We will find someone. Now perhaps it would be best if you returned above. Inari-Okami will have sensed that… explosion, surely?”

“Ah. Good point! Um.. sorry about the mess. Oh, can someone copy my notes down please? I might need them. Oh and be careful with that bronze club thing. it’s probably carrying a fairly potent charge right now and who knows what that might do.”

“Paul-sama...”

“Ah, right. Ok, I’ll be... going, now. I have quite a bit to do anyway.”

Paul felt somewhat embarrassed and a bit despondent as he headed away from the mine. He’d gotten carried away, again. He’d forgotten the social niceties as he was swept up in his enthusiasm and mono-focus ‘mode’. In all probability he wouldn’t be welcome back there again. He just hoped he hadn’t offended the Oni too much. Apart from anything else, they had control of the source of magic, or at least, a source.

Paul frowned thoughtfully. He still wasn’t sure why it had gone off like that though. The steady pressure should’ve produced a steady power output. His best guess was that the piezoelectric effect generated a current which had in turn had generated a magnetic field, which interacted with paramagnetic properties of the tourmaline to produce a back induction current, cancelling out the field until it faded, and thus produced a power spike. So, the total power output hadn’t really been greater, just more compressed into a shorter duration. Although how that interacted with whatever mechanism was turning it into magical energy was anyone’s guess.

Paul sighed. He imagined this was how the early pioneers of physics must have felt when investigating electricity and magnetism. Not the slightest idea why it worked, but at least some idea how.

Still, he thought as the workshop came into view; if you don’t have theory to rely on there’s always trial and error, and I suppose it wouldn’t hurt if I spent an hour or so mucking about with it, just to see if I can figure out some of the basic properties...