Japan stock index soars 5 percent, yen falls after BOJ announces new stimulus

Japan's Nikkei 225 stock average surged 5 percent and the yen slid against the dollar after the Bank of Japan unexpectedly announced new stimulus to boost a flagging economic recovery.

Other Asian stock markets were also higher after the Japanese central bank's announcement Friday. The dollar rose 1.2 percent to 110.64 yen.

The bank said it would increase its asset purchases by between 10 trillion yen and 20 trillion yen ($90.7 billion to $181.3 billion) to about 80 trillion yen ($725 billion) annually.

The Nikkei was up 4.6 percent at 16,380.11 after shedding some of its initial gains. Hong Kong's Hang Seng rose 1.2 percent and Seoul's Kospi was up 0.1 percent.