1) 1,182 listed 163 ( China) 240 were from the Korean peninsula. ( New World Encyclopedia) 

 2) Korean roots of ' Genji' written by William Wetherall from Japan Times Online. 

 Heiankyo, which Kanmu built a few years after is mother death was heavily populated by clans with Korean roots. " Shinsen Shojiroku", a peerage compiled in 815 shortly after 
 Kanmu death, lists 1,182 imperial and other clans of which 326 ( 28 percent) were of non indigenous mostly Korean origin, over half of the immigrant clans resided in 
 Heinkyo, now Kyoto.