The most controversial of Kublai 's policies , however , was opening the tombs of the Song emperors to gain treasure for the treasury .
The most controversial of Kublai 's policies , however , issuing large amounts of notes which caused hyperinflation .
The most controversial of Kublai 's policies , however , was opening the tombs of the Song emperors to gain treasure for the treasury , and issuing large amounts of notes which caused hyperinflation .