Kaji is a respectful title given to certain castes in Nepal.
After Shri Paanch Bada Maharaj Dhiraj Prithvi Narayan Shah formedGreater Nepal,he honored five castes with the hereditary title of "Kaji". Initially, four castes Basnyat, "kunwar", Pandey" and Thapa. This honorary hereditary title is in existence even in today's time as respective 5 castes are till date corresponded to with the title "Kaji" prior to one's family name.
The respect that is to be provided to these elite classes of Kshatriya was even implemented to the likes of Brahmans, the highest of the Hindu castes.
Similar, another form of Kaji System came into existence much later which was non-hereditary. The title 'Kaji' was provided to the representative of the people's governing body. As it was a non-hereditary title, this term was only enjoyed by the personal till he was incumbent to the King and the people.
Other kaji as Rajbhandari,Pradhan,Bharo,and Bhandel Kaji still exits in Newa: society
,the Newa: rigime did had kaji in thier palace,the kaji honour did exits since the sanatan period.