* Topix falls 0.1 pct; Nikkei up 0.6 pct thanks to Fast Retailing
* Investors reluctant to buy ahead of earnings season,10-day break
By Tomo Uetake
TOKYO, April 12 (Reuters) - Japan's Nikkei share average rose on Friday but was little changed for the week, as many investors stayed on the sidelines ahead of the U.S. and domestic earnings season and an upcoming 10-day holiday in Japan.
The benchmark Nikkei ended the morning session at 21,841.90, up 130.52 points, or 0.6 percent, on the day, largely thanks to its heavyweight Fast Retailing Co Ltd, which soared 7.8 percent to contribute a hefty 160 points, or 0.7 percent, to the Nikkei.
The operator of Uniqlo slightly cut its full-year profit forecast after unusually warm weather forced it to slash prices for winter clothes, but the number will still be a record high as its business in China continues to be strong.
The broader market was not as rosy as the Nikkei might suggest, with the Topix index dropping 0.1 percent to 1605.39.
"There are multiple reasons for investors not to buy stocks now. Earnings season is coming up in the United States and Japan, and we are heading into the 10-day holiday period here," said Yasuo Sakuma, chief investment officer at Libra Investments in Tokyo.
To mark the ascension of Japan's new emperor, the government has declared an unprecedented 10-day holiday from April 27 to May 6, which will the longest break ever for Japanese stocks and bonds.
Yaskawa Electric Corp, which usually kicks off Japanese earnings season, shed 0.5 percent after the industrial robot maker forecast operating profit for the current business year through February to fall 6.6 percent.
Lawson Inc was the worst performer on the main board, diving 12.4 percent, after the convenience store operator cut its dividend forecast for the current financial year by 41 percent.
Other notable movers include SoftBank Group, jumping 3.0 percent, after Uber Technologies Inc filed for an initial public offering, paving the way for the U.S ride-sharing company to go public next month. SoftBank is Uber's biggest investor. (Reporting by Tomo Uetake; Editing by Kim Coghill)