In early trade, the Nikkei 225 was off 5.4 percent, having soared 9.1 percent on Thursday after US President Donald Trump paused many tariffs for 90 days.
Other markets also handed back many of their gains of the previous day, with the Kospi in Seoul off 1.64 percent and Sydney down more than two percent.
Oil and the dollar also slid on fears of a global slowdown in economic activity, while gold hit a new record.
Fellow safe-haven asset the yen also gained 0.9 percent against the dollar on Friday.
Trump maintained a 10 percent blanket tariff on most countries.
But he paused plans for tariffs of 20 percent on the European Union and even higher levies on multiple other trade partners, including 24 percent on Japan.
However the levies on China, which has retaliated with tariffs on US good, were not only maintained but hiked further.
The White House on Thursday clarified that levies on Chinese imports are now at a total of 145 percent. (AFP)
