One theory by Yoshiyuki SUDO, Toshikazu HORI and so on is that with the demise of the Equal-field system, the land ownership principle by peasant folks collapsed, the large landholding began, the owner and the denko were born and in the Sung dynasty the class of owners became the bureaucrats who came to manage shoens using the denkos.
1つは周藤吉之・堀敏一らの説で均田制の崩壊で小農民による土地所有原則が崩壊して大土地所有が発生して地主と佃戸が形成され、宋代に入ると地主層が官僚となり佃戸を駆使して荘園を経営するようになった。