https://www.bbc.com/news/articles/crklvx2n7rzo
What happened? A timeline
The current tensions were sparked at a parliamentary meeting in Japan on 7 November, when an opposition lawmaker asked Takaichi what circumstances surrounding Taiwan would count as a survival-threatening situation for Japan.
"If there are battleships and the use of force, no matter how you think about it, it could constitute a survival-threatening situation," Takaichi responded.
A "survival-threatening situation" is a legal term under Japan's 2015 security law, referring to when an armed attack on its allies poses an existential threat to Japan. In such a situation, Japan's self-defence forces can be activated to respond to the threat.