Japanese stocks gained marginally on Friday after US Treasury yields steadied, while investors remained cautious ahead of Federal Reserve Chair Kevin Warsh's speech at Jackson Hole on the outlook for US interest rates.

The benchmark Nikkei 225 closed up 273.58 points, or 0.41%, at 66,405.56.

Oil prices extended losses following an Iran-Oman deal to impose a tariff on traffic in the Strait of Hormuz on a revenue-sharing basis, even as hopes of direct US-Iran talks remain uncertain.

On the corporate side, Nissan Motor's (TYO:7201) global sales fell about 17% year over year to 219,495 units in July, according to a statement on Friday.

Also, Toyota Motor (TYO:7203) posted its sixth consecutive drop in worldwide monthly sales in July, with group-wide volume falling 5.3% year over year to 912,683 vehicles, according to company data released Friday.