* Nikkei poised to post 6th weekly gains
* Profit-taking may be possible before Christmas break - analysts
* Nintendo tumbles after market prices in Super Mario Bros launch on iPhones
By Ayai Tomisawa
TOKYO, Dec 16 (Reuters) - Japan's Nikkei share average rose on Friday, set to mark a nine-day rally after tracking gains in strong U.S. shares while weak yen continued to help overall sentiment.
The Nikkei gained 0.7 percent to 19,404.75 in midmorning trade, extending its gains into a ninth day, which would be the longest winning streak since May 2015.
For the week, the benchmark index has risen 2.2 percent and is expected to post its sixth weekly gain.
The dollar rose 0.1 percent against the yen at 118.33 yen after rising as much as 1.4 percent to 118.66 yen, its highest since early February.
Traders said that while many investors enjoy the strength in the stock market, some investors were cautious about the timing of profit-taking, given the high-speed surge in the Japanese market.
"We may expect some profit-taking before foreign investors go on a Christmas break," said Takuya Takahashi, a strategist at Daiwa Securities. "They are somewhat cautious about the current rally."
A total of 28 of 33 Topix's subsectors were rising, with banking stocks outperforming.
Mitsubishi UFJ Financial Group rose 1.8 percent, Sumitomo Mitsui Financial Group gained 1.3 percent and Mizuho Financial Group added 1.7 percent.
Exporters, the big beneficiaries of the weak yen, were mixed as some investors are cautious about their sharp gains over the past month. Toyota Motor Corp fell 0.5 percent, Honda Motor Co added 0.7 percent and Tokyo Electron Ltd rose 2.9 percent.
Nintendo Co tumbled more than 5 percent after retail investors and short-term investors saw that the stock price has already priced in news of the launch of its Super Mario Bros franchise on the iPhone.
The broader Topix rose 0.5 percent to 1,550.15 and the JPX-Nikkei Index 400 advanced 0.6 percent to 13,880.60. (Reporting by Ayai Tomisawa; Editing by Eric Meijer)