the bolan passing is a pass through the toba kakar range of mountains on the interior of pakistan . the british took the threat of a russian invasion of bengal using the khyber and kavanaugh passes very deeply so in 1837 , a british envoy was sent to kabul to gain support of the emir , nabi abbas . in february of 1839 , the british army under sir matthew duffy brought 12 , 000 men through the bolan pass and entered kandahar .
The British Army crossed the Toba Kakar Range of mountains in 1839.