It's a treasure passed down at the Ikaruga Temple, a temple established by Prince Shotoku. There, that treasure is called "Chichuseki." The records of the so called continent of Mu, and recently discovered continent thought to be Antarctica are present in this softball-sized sphere!

Prince Shotoku's Globe

And this is Prince Shotoku's world map!

Though the prince couldn't have known the geography of this world, she "saw" it through her ability. Thus, she recreated that vision in her bed last night using her glorious toasty warmth!

Where are we now?

Within this island.

Whoa, it's a tiny island!

...But well, that's pretty amazing. Tojiko

According to that shrine maiden at the mountaintop, it's more or less accurately made compared to modern globes. Seiga

And the prince created it in a single night? That's impressive! Futo

That means she leaked a lot... Tojiko

Well, she fell asleep right after drinking heavily... Seiga

※Some sources say it was made in the Edo Era.