Sonpi Bunmyaku, the biographies of the nobles and humbles (尊卑分脈)

Sonpi Bunmyaku is a text compiled in early Japan that records the lineages of the aristocracy. The full title is "Shin-Hensanzu-Honcho-Sonpi-Bunmyaku-Keifu-Zatsurui-Yoshu." Generally, however, this long name is shortened to "Sonpi Bunmyaku". It is also known as "Shoke-Okeizu."

It is one of the basic books for research and investigation of family names, and was completed over a period spanning from the period of the Northern and Southern Courts (Japan) to the beginning of the Muromachi period. The book was edited by Kinsada TOIN (1340-1399), and mainly compiled from 1377 to 1395. After Kinsada's death, various members of the house of TOIN, including his adopted son, Mitsusue TOIN and his grandson, Sanehiro TOIN, continued to edit, alter, correct, and make additions. After the Muromachi period, the book was drastically enlarged and revised and a number of differing editions were circulated, including an edition in 30 volumes, an edition in 20 volumes, and an edition in 14 volumes.

When first written, a genealogical table of the Imperial line, a genealogical table of the gods, and a genealogical table of astrology appear to have been included, but these have been lost, with the surviving books being especially detailed on the Fujiwara and the Minamoto clans (because both had taken over key positions in the court society) among the distinguished families which included the Minamoto, the Taira, the Fujiwara, and the Tachibana (also known as the Gen, Pei, To, Kitsu due to Chinese readings of the characters in their names). In the book, the paternal line is represented as a straight line, and women, except for empresses and a handful of others, are nameless, being described merely as "women" (even famous women such as Shikibu MURASAKI remain nameless). For male government officials, the genealogical tables contain real names and abbreviated biographies, including mother's name, official position, date of death, age at death and footnotes, making the book an extremely valuable source of information. The records of the Heian and the Kamakura periods are recognized as a historical source of the highest value. The section written after Kinsada's death requires a more critical approach and has to be checked against other sources. The same goes for other added sections.