The concept of 'Kuhon Ojo' is advocated in 'Kanmuryoju-kyo' (The Sutra of Visualization of the Buddha of Measureless Life, meaning Amida), which preaches that there are nine stages or categories on Gokuraku Ojo (to rebirth from this world into Amitabha's Western Pure Land Paradise) from those who correctly adhere to Buddhist teachings to the most evil people.
「九品往生」とは「観無量寿経」に説かれる思想で、極楽往生（人が現世から阿弥陀如来のいる西方極楽浄土へと生まれ変わる）のしかたには、仏の教えを正しく守る者から、極悪人まで9つの段階ないし種類があるという考えである。