Thailand. (Laotian Civil War). 1971. Stamp-less envelope addressed to Bangkok cancelled by Bangkok date stamp '2nd Sept 1971' with framed 'Royal Thai Army Border Patrol' with 'Censor/ Checked' cachet in violet, signed by the Commanding Officer.
Royal Thai Army Troops were on the Thai Laos border as part of 'Operation Phalat' a military offensive during the Laotian Civil War.