Why did the Japanese yen appreciate significantly after Brexit?

Because funds need to be hedged. If Brexit is successful, the exchange rate will plummet and massive amounts of funds will have to jump out of the pound and eurozone. A better way at this point is to invest in gold, silver, or other relatively stable currencies. In fact, not only is the Japanese yen rising now, but the US dollar is also rising, but it's just that it's not rising as much as the Japanese yen.

Moreover, in the current international community, Japan has a large economic position, but lacks political autonomy. It's typical of not doing what you want and who you want to do what you want?