Corn and wheat futures also rose at the Chicago Board of Trade. Short covering and technical buying helped lift prices after the grain and soy markets neared one-month lows this week, analysts said.
Soy traders are eager for China to buy more US cargoes after China purchased American soybeans on Dec. 12 in the first big deals in six months. The sales came after US President Donald Trump and his Chinese counterpart Xi Jinping met on Dec. 1 and set a 90-day negotiating window to resolve their trade differences.
China then made a second wave of purchases, the US Department of Agriculture confirmed on Dec. 19, fueling expectations that more deals will be done.
"Everybody's looking for them," said Jack Scoville, vice president of Price Futures Group in Chicago.
The most actively traded soybean contract jumped 16-1/2 cents to $8.99 a bushel by 12:15 CST (1815 GMT).
Corn gained 1-1/2 cents to $3.76 a bushel while wheat was up 1-3/4 cents at $5.12-1/4 a bushel.
Positioning helped propel prices higher after recent declines.
"They pushed it down fairly easy to start the week," said Jason Britt, president of Missouri-based broke Central States Commodities.
Optimism that Washington and Beijing will make progress to resolve the trade war also helped boost prices, traders said. China is the world's biggest soybean importer and all but halted purchases from the United States before the trade truce.
On Thursday, the Chinese commerce ministry said China and the United States had plans for more face-to-face consultations over trade in January.
China separately opened the door to imports of rice from the United States in what analysts took to signal an easing of tensions.
"I believe it's happy feet over statements that came mostly out of China pointing to a thaw in the relations," Scoville said about the soy rally.
The US Department of Agriculture's weekly export sales report, which had been scheduled for release on Friday, has been postponed indefinitely due to a partial US government shutdown. The USDA is also not publishing daily export sales announcements because of the shutdown.