What modern prefecture does the ancient Japanese place name 'Wanokuni' correspond to?

Kunihide Kunitachi is my best friend.

The system of provinces was a part of the ancient political system in Japan.

He is interested in geometrical shapes.

He often thinks about problems from a humanitarian perspective.

His company is facing the risk of a hostile takeover.

He is spending a lot of time on experimental research.

That plan is too impractical, it's difficult to implement.

His plan was so unrealistic that no one could believe it.

This painting depicts a surreal landscape.