By late 1944, it was becoming apparent that B-29 operations against Japan staged out of bases in China and India were far too expensive in men and materials and would have to be stopped. In December 1944, the Joint Chiefs of Staff made the decision that Operation Matterhorn would be phased out, and the 58th Bombardment Wing's B-29s would be moved to newly captured bases in the Marianas in the central Pacific. The last raid out of China was flown on 15 January 1945, which was an attack on targets in Formosa (Taiwan). The 58th Bombardment Wing then redeployed to new bases in the Marianas in February.