Equal Temperament and Just Intonation

♪Poet (Present)♪

In the middle of battle, a mystery that had lingered throughout history was suddenly solved.

According to the history books, female-voiced warriors were by no means rare in prehistoric times, in antiquity, or even in the early Middle Ages.

But from a certain point onward, only men were the ones using offensive magic, and the figures who appeared in military history became overwhelmingly male.

That shift had taken place roughly four hundred years ago.

Yes.

It lined up exactly with the era when the five-line musical staff was invented, when frets were added to the guitar, and when keyboard instruments adopted equal temperament.

Equal temperament.

It was a newly invented technology designed to stabilize the pitch of instruments. With its introduction, the effects of male vocal magic could be supplied consistently and reliably, and people said it marked the beginning of the era later called the Magic Renaissance.

But in exchange, the ancient mode of tuning that had been handed down continuously from antiquity—just intonation—was lost.

And if that was true, then there was no doubt about it:

The secret behind female vocal magic being able to cast powerful offensive spells lay in just intonation.

“Let’s run while we still can!”

“Y-yes!”

I grabbed her hand and ran.

Then I hoisted her onto my back and sprinted with all my strength.

“You’re not getting away!”

“Wh-what?!”

I’m one of the rabbitfolk. Not an actual rabbit, but a demi-human of part-beast blood. I’m confident in my speed.

And yet the enemy was catching up at nearly the same pace, weaving through the trees in pursuit.

Dragonfolk...

It wasn’t just that his instrument was excellent—his body itself was powerful.

“Take this!”

He played a short phrase in the blues scale and sent pebbles flying at incredible speed.

“Gah!”

I lost my footing, slammed into a tree branch, and was thrown aside. She... let out a groan. She might be okay—or she might not.

“This time I’ll finish it. Take this—Master Fire, the superior spell to Basic Fire!”

A massive blaze roared forth, enough to start a forest fire. Against it, Ms. Adagio answered with Basic Ice, the minor-key variant of Basic Fire.

No matter how much just intonation strengthened it, it was still not a spell that could stand against Master Fire. Little by little, she was being overwhelmed.

Damn it. I couldn’t just stand here and watch.

Accompaniment!

I had to support her with accompaniment!

I pulled out my guitar.

No good!

Her singing was in just intonation. If I played a modern instrument like this, I’d create dissonance. And if I played dissonance, the magic’s effect would weaken.

That’s it!

A lute!

I had a lute!

Casting a male vocal spell, I pulled a lute out from subspace. My lute had no frets—in other words, it was not tuned for equal temperament. It was an ancestor of the guitar, a traditional instrument said to have been used by medieval minstrels for sung storytelling.

With this, I could play the music of ancient times!

But it was really little more than a replica. It could produce sound, yes—but it had not been processed as a magic instrument.

Was this the end?

No. Not yet.

I couldn’t give up.

“Lala♪”

I summoned a Phillips screwdriver from subspace and removed a certain device from the folk guitar in my hands.

The device was called the Fourier Connector.

In the early days of instrumental magic’s spread, only handmade products from certain parts of the Lyodia region had existed. These were devices that cast magic directly through the instrument itself. But the early models were unstable in performance—not nearly good enough to be called true upgrades over vocal magic. There were certainly talented users and skilled makers, but at the same time, cheap, inferior copies made by amateurs spread everywhere. The prejudice against instrumental magic that still existed today had been born in that period.

What had revolutionized the status of instrumental magic was this very Fourier Connector. Even an ordinary performance instrument could produce high-performance instrumental magic simply by attaching one of these.

I’d heard that people from the other world compared it to the moment automatic transmissions appeared in a world of manual cars.

The inventor of the Fourier Connector was someone called Associate Professor Lala. Apparently she was half demon, and was active in raising the standing of both humans and demons by serving as a bridge between them. I’d like to meet her someday.

But that was beside the point.

The lute had no screw holes.

Still, I had to attach it somehow. I had no choice. I’d just have to glue it on with instant adhesive. But if I did that, I’d never be able to remove it again.

“To hell with it! I’m going all in!”

I smeared a clear liquid onto the lute, then slapped the little box-shaped device onto it.