The Demilitarized Zone Peace Preservation Corps was a police force created by the 1933 Tanggu Truce between China and Japan in the aftermath of the Japanese invasion of Manchuria.
Its role was to patrol and maintain order in the demilitarized zone extending from south of the Great Wall, to a line north east of the Bai River in Hebei province in northern China.
Within the zone itself, which partially encompassed the major cities of Tianjin and Beijing, public order was to be maintained by a lightly armed “Peace Preservation Corps”.
Per the terms of the Tanggu Truce, any disputes that could not be resolved by the Peace Preservation Corps would be settled by agreement through direct discussions between the Japanese and Chinese governments.
A secret clause of the Tanggu Truce excluded any of the Anti-Japanese Volunteer Armies from the Peace Preservation Corps.