New Delhi, July 2 -- RIYADH - Saudi Aramco prefers certainty. Nearly all of the state oil company's global crude sales run on long-term supply agreements, the kind that lock in buyers, pricing stability, and relationships years in advance. That preference gave way this week as Aramco moved at least 6 million barrels through the spot market, selling to buyers in South Korea, Japan, and China outside its usual contractual framework.

Saudi Arabia is moving fast to make up for lost time.

The numbers are specific. At least 6 million barrels went to buyers in South Korea, Japan, and China on spot terms, compared to the long-term contracts with fixed delivery schedules that define most of Aramco's trade. That four supertankers capable of carry...