Complete the expand the Kokka in Japanese missions

Hello, I’m a new player and I decided to start my first campaign with Tokugawa in 1618 (when they control most of Japan). I managed to form Japan (I mean changing the name of it from Tokugawa to Japan on the map) and I control all the isles including the northern ainus, I achieved the « Pacify the north » mission but I’m still stuck with « Expand the Kokka ». I don’t get why it says that I still need to control 2 states.

I thought states were group of territories, and as I control all of the Japanese isles, I control more than 2 states, but it seems I’m wrong.

Any idea on how I can achieve the mission?