New Delhi, April 10 -- With a fragile ceasefire agreement between the U.S. and Iran holding for now, China is calculating its role in helping find a durable endgame to the war in the Middle East.

After prodding China, which is more reliant on Persian Gulf oil than the U.S., to get involved in reopening the choked-off Strait of Hormuz, President Donald Trump told the French news outlet Agence France-Presse this week that he believed China played a part in encouraging Iran to agree to this week's temporary truce.

Three diplomats who were familiar with China's behind-the-scenes efforts also confirmed that Beijing, the biggest purchaser of Iranian oil, used its leverage to urge the Iranians back to the negotiating table.

It was a major mom...