For the 1182 clans that lived in Heian-kyo (the ancient capital of Japan in the current Kyoto) and the Kinai region (the five capital provinces surrounding the ancient capitals of Nara and Kyoto), "Shinsen Shojiroku" describes the origin of their family names, how the pedigrees branched and other information by classifying the clans, based on the place of origin, into 'Kobetsu' (clans that branched out from the Imperial Family), 'Shinbetsu' (clans the branched out of the family of god) and 'Shoban' (clans coming from foreign lands) to clarify their ancestors; however, it was compiled mainly to determine whether the changed family names of the clans were accurate.
『新撰姓氏録』は、平安京および畿内に住む1182氏を、その出自により「皇別」・「神別」・「諸蕃」に分類してその祖先を明らかにし、氏名（うじな）の由来、分岐の様子などを記述するものであるが、主として氏族の改賜姓が正確かどうかを判別するために編まれたものである。