How can I get Kozuke-no-Sanada to attack me

[wealthmonger]

I made the mistake of giving them unlimited military access, I don't know what I was thinking. I don't want the diplomatic hit from attacking them so how can I get them to attack me.

They have no allies, no trade partners, no enemies. It's 6 years later then the pic below and no change. Uesugi switched alignment to tokugawa but were still allied. Asano is my vassal controlling kai, north shinano and south shinano. Causing rebellions in their territory until the rebels succeed is that the only way to eliminate them?

I'd rather defeat them in battle but I can't figure out how to get them to turn on me. Our relations are now at -124 but still they sit there being nice and peaceful with their stack and a half. I've been pushing towards central honshu. I guess I'm just frustrated by the lack of action on that side of my territory.

Spoiler Alert, click show to read: 

[Akaie]

If you want their territory, it seems the only way to save face is to grind them down with rebellions. Definitely re-think military access in the future .