The yen has three main movers that you need to know about.
1. The Japanese Yen is typically traded as a safe haven currency. In times of disaster, uncertainty. or poor global trade outlook (like the US-China trade war) the Yen finds buyers.
2. This is the other side of the coin of being a safe haven currency. When the market is feeling confident and optimistic (Stocks rallying) , the YEN finds sellers and it weakens. So, the JPY operates as a risk currency that traders rotate into and out of depending on the mood of the day.