Colonel Mason remained in command of 1st Marines after the Okinawa campaign and spent almost three months stationed at division camp at Motobu Peninsula.
Mason and his regiment were subsequently ordered to Tientsin, China on September 30, 1945.
Its mission was to assist in the repatriation of Japanese troops from North China.
The 1st Marines also took part in the guard duty of property and rounded up Japanese repatriates.
Mason and his units came often under fire of Chinese Communist guerrillas.

Because of the constant threat of communist attack on the bridges and railway supplies, his marines were used also for guard duty of these.
Mason remained in China until September 19, 1946, and subsequently returned to the United States.
For his service in connection with repatriation of Japanese troops, Mason received his second Legion of Merit by the Army.
He also received Order of the Cloud and Banner, 5th Class by the Government of Republic of China.

Following his return stateside, Mason was ordered for the course to Armed Forces Staff College at Norfolk, Virginia.
After his graduation, he served for more than two years as faculty member and subsequently was ordered to Joint Chiefs of Staff under General Omar Bradley.

His final assignment came in August 1950, when Mason was ordered to San Francisco, California, and appointed chief of staff, Department of the Pacific under Major General Ray A. Robinson and later under Henry D. Linscott.
Briefly before his retirement, Mason also served as deputy commander of that command.
He finally retired from the Marine Corps after 31 years of service in May 1954.
Mason was promoted to the rank of brigadier general for having been specially commended in combat.
Colonel Mason remained in command of 1st Marines after the Okinawa campaign and spent almost three months stationed at division camp at Motobu Peninsula. Mason and his regiment were subsequently ordered to Tientsin, China on September 30, 1945. Its mission was to assist in the repatriation of Japanese troops from North China. The 1st Marines also took part in the guard duty of property and rounded up Japanese repatriates. Mason and his units came often under fire of Chinese Communist guerrillas.
Because of the constant threat of communist attack on the bridges and railway supplies, his marines were used also for guard duty of these. Mason remained in China until September 19, 1946, and subsequently returned to the United States. For his service in connection with repatriation of Japanese troops, Mason received his second Legion of Merit by the Army. He also received Order of the Cloud and Banner, 5th Class by the Government of Republic of China.
Following his return stateside, Mason was ordered for the course to Armed Forces Staff College at Norfolk, Virginia. After his graduation, he served for more than two years as faculty member and subsequently was ordered to Joint Chiefs of Staff under General Omar Bradley.
His final assignment came in August 1950, when Mason was ordered to San Francisco, California, and appointed chief of staff, Department of the Pacific under Major General Ray A. Robinson and later under Henry D. Linscott. Briefly before his retirement, Mason also served as deputy commander of that command. He finally retired from the Marine Corps after 31 years of service in May 1954. Mason was promoted to the rank of brigadier general for having been specially commended in combat.
Arthur T. Mason