Let's be honest, Shugoki is slow.
His attacks are so slow that the opponent usually hits first so most of the time Shugoki has to rely a lot on his unstoppable stance to trade blows with the opponent.

How to easily get him out of that stance? Guardbreak. It does not even have to be successfull. Shugoki can counter it, but it still gets him out of Unstoppable stance and he is vulnerable for several nerve-wrecking seconds. And there is nothing he can do for it.

Hey, Shugoki, your stance is up? I Guardbreak. You countered it? I don't care, it still made you vulnerable, the job is done.

GB is basically a win-win move for the opponent.

My suggestion is - When Shugoki has the unstoppable stance up and he counters a GB, put the stance back up immediately. Maybe even if he was vulnerable. That way the opponent will think twice before trying to GB.