Underwear

1.

There is something called a communication crystal in this world.

It captures and displays the other person's face and surroundings on its surface.

In terms of the technology from my previous life, you can think of it as roughly equivalent to an internet video call.

The only problem is that it definitely isn't a telephone,

and two crystals are paired together, allowing them to connect only with their designated counterpart.

In other words, it isn't a system where you dial a number and call whoever you want.

You can think of each crystal as having its call recipient predetermined.

That is why the imperial family usually distributes one to each household.

If you want to contact the ducal house, you have to use the crystal paired with the ducal house's...