You can infer ignorance from a simple paragraph i knocked out and discount my opinion
My assessment that Japan would be willing to fight isn't based on assuming any love for Taiwan, it's based on their repeated policy statements that they would fight against a militarily expansionist PRC backed by their force structure designed to accomplish this.
My assessments are based on knowledge gained in nearly 20 years as an East Asia/Asia-Pacific analyst. I've also lived on Taiwan on and off for a total of 6 years so far and taught IR courses at one of their leading research universities. I'm not assuming anything, I know it.