With confidence in the free-trade system shaken, mainly by the heated tensions between the United States and China, ensuring trade friction doesn't weaken the global economy will be a major item on the agenda at the Group of 20 leaders' summit this week in Osaka.

According to economists interviewed by The Japan Times, the biggest risk to the world's economy is the U.S.-China trade row. Some said the potential spillover effect would inflict enough damage to chill the economy, though they believe a recession would be unlikely.

The trade war could also deal a blow to the Japanese economy, which has seen few positive signs in recent months amid weak consumption and corporate earnings, and an October consumption tax hike to 10 percent from 8 percent just months away.