Shigeru Ishiba will face five key challenges when he becomes Japan's new prime minister on Tuesday after being voted leader of the ruling Liberal Democratic Party .
The yen weakened after Shigeru Ishiba suggested the Bank of Japan shouldn’t tighten monetary policy too quickly.
In contrast, Japan’s Nikkei 225 index tumbled nearly 5% on Monday, and the yen weakened against the dollar as traders reacted ...