The 12th Sentai was redeployed to the Mongolian-Manchurian border to fight in the Battle of Khalkhin Gol, but when this conflict ended, in September 1939, the BR.20s were progressively withdrawn and replaced by the Ki-21. Despite having been phased out from operational service, the BR.20 was allocated the Allied reporting name "Ruth".Taylor 1980, p. 384.
