* Nikkei has gained 0.9% on weekly basis so far
* Sony jumps 4% after Third Point calls on firm to spin-off chip unit
* Market focuses on FOMC
By Ayai Tomisawa
TOKYO, June 14 (Reuters) - Japan's Nikkei edged up on Friday, with oil shares rallying after attacks on two oil tankers in the Gulf of Oman stoked concerns of reduced crude flows through one of the world's key shipping routes.
Sony Corp was in the spotlight, with the stock rallying as much as 4% after Daniel Loeb's activist hedge fund Third Point LLC called on the company on Thursday to spin off its semiconductor business and sell off stakes in Sony Financial and other units.
The Nikkei share average tacked on 0.2% to 21,066.26 in midmorning trade, after slipping into negative territory earlier. For the week, the index is up 0.9%.
Nikkei 225 futures and options contracts expiring in June will likely settle at the price of 21,060.56, according to estimates by brokers. The closely watched settlement price, known in Japan as the special quotation, or SQ, is calculated from the opening prices of the 225 shares in the Nikkei share average on the second Friday of the month.
The official figure is due out after the market closes on Friday.
The mining and oil sectors were top performers on the board after oil prices surged on Thursday. Inpex Corp rose 1.3%, Japan Petroleum Exploration Co gained 1.1%, while Idemitsu Kosan surged 2.2%
It was the second time in a month tankers have been attacked in the world's most important zone for oil supplies, amid rising tensions between the United States and Iran. Washington quickly blamed Iran for Thursday's attacks, but Tehran denied it was responsible.
"While there is strong demand in oil-related shares amid the oil sector's volatility, most investors are cautious about taking positions before big events later this month," said Takatoshi Itoshima, a strategist at Pictet Asset Management.
He said investors are looking to next week's U.S. Federal Reserve meeting for cues on a possible interest rate cut in the wake of mounting risks to trade and global growth.
Financial markets also remain on edge ahead of a possible meeting between U.S. and Chinese leaders at the G20 summit in Japan later this month, as trade tensions between the world's biggest economies showed no signs of letting up.
The gains in oil shares triggered buying in other commodity-related stocks such as metal producers. Mitsubishi Materials gained 1.3% and Mitsui Mining & Smelting jumped 1.8%.
The broader Topix rose 0.2% to 1,544.93. (Editing by Shri Navaratnam)