Tokyo  - Japan's key Nikkei 225 Stock Average Monday crossed the 9,000-point threshold, up more than 5 per cent thanks to a strong rally on Wall Street last week and the US dollar's advance against the yen.

The Nikkei index soared 498.43 points, or 5.81 per cent, to close at 9,081.43.

The broader Topix index of all first-section issues was also up 37.65 points, or 4.28 per cent, to 916.65.

On currency markets at midday (0300 GMT), the dollar was quoted at 99.12-17 yen, up from Friday's 5 pm quote of 97.58-60 yen. A weaker yen helps boost Japanese exporters' earnings.

The euro was quoted at 1.2864-69 dollars, up from Friday's 5 pm quote of 1.2776-78 dollars, and at 127.58-63 yen, up from 124.67-71 yen. (dpa)