About the USD to JPY rate
USD/JPY has spent long stretches reflecting the gap between US and Japanese interest rates — when that gap widens, the yen has tended to weaken as investors borrow cheaply in yen to invest in higher-yielding dollar assets, a dynamic traders call the carry trade.
For travelers, Japan's reputation as a relatively affordable destination for US visitors can shift quickly with this exchange rate — a weaker yen meaningfully stretches a dollar-denominated travel budget, while a stronger yen narrows that advantage.
Japan's Ministry of Finance and the Bank of Japan have intervened directly in currency markets in the past when they judged yen moves to be too rapid, which is worth knowing if you notice an unusually sharp short-term move in this pair.