According to KAIGUN, by David C. Evans and Mark R. Peattie, the IJN had no need to develop and practice refueling at sea until planning for the offensive operations in the Pacific, "By mid-1941, however, the fleet was beginning to work out underway replenishment for fuel oil." Of course, then they learned quickly.
The USN had begun to develop underway replenishment in WWI and returned to working out the practice in the 1930s. See:
Gray Steel and Black Oil Fast Tankers and Replenishment at Sea in the U.S. Navy, 1912-1995, by
and the article "Chester Nimitz and the Development of Fueling at Sea" by the same author in the Autumn 1993 issue of the NAVAL WAR COLLEGE REVIEW