* Exporters gain ground
* Takeda soars on news of tie-up with AstraZeneca
TOKYO, Aug 30 (Reuters) - Japan's Nikkei share average rebounded on Wednesday morning, recovering from a near four-month low as Wall Street rose and the yen weakened on receding concerns over North Korea's firing of a missile over Japan.
The Nikkei rose 0.6 percent to 19,481.44 in mid-morning trade.
North Korea's launch of a ballistic missile over northern Japan's Hokkaido island into the sea on Tuesday had triggered steep losses in the market, sending the Nikkei to the lowest since May 1.
Traders said North Korea-related concerns may persist and the Nikkei may fall 100-200 points if it happens again. But they added that such concerns can fade quickly when stock valuations become cheap and investors bargain hunt for firms with a strong outlook.
"Yesterday's incident is considered to be one of those threats by North Korea. Unless there is military action taken by either North Korea or the United States, the market will likely rebound quickly," said Toru Ibayashi, executive director of Wealth Management at UBS Securities in Tokyo.
Exporters gained ground after the dollar last traded at 109.78 yen, having recovered from Tuesday's low of 108.265 yen, which was the dollar's lowest since mid-April.
Isuzu Motors gained 1.1 percent, Panasonic Corp added 0.7 percent and Keyence Corp rose 0.9 percent.
Takeda Pharmaceutical soared 1.5 percent on news the drugmaker would partner with AstraZeneca to develop an early-stage medicine for Parkinson's disease.
Elsewhere, Dunlop Sports jumped 14 percent after the sports goods maker said it would merge with Sumitomo Rubber Industries.
The broader Topix gained 0.4 percent to 1,604.32. (Editing by Jacqueline Wong)