exploring 片胸捕 Katamune Dori. The name of the kata is descriptive of the attack. It means grabbing one side of the mune, or chest. This is 高木揚心流柔体術 Takagi Yoshin Ryū Jūtaijutsu, so the response will reflect the strategies from that school.
Use the cover unique to the school. Then break the grip. Not with your hands but with your body! When I trained with Hatsumi Sensei in December, he described it as seperating yourself from the attack. This can be understood on many levels. In fact, at one point he said we must become “almost like a (妖怪 youkai) spirit or a monster.”