Asian markets had a wild start to the week, with Tokyo’s Nikkei 225 index tumbling nearly 5% while Chinese markets soared on news of fresh stimulus for the faltering economy, with Shanghai up more than 7%.

Stocks dropped after Japan’s governing party chose Shigeru Ishiba, a critic of the country’s longstanding ultralow interest rates, as its leader.

As Japan’s ruling party gets set to vote for a new leader who will then likely become the nation’s next prime minister, traders are preparing for the potential impact on the yen and shares of exporters,