ðɪs kˈæst sˈɪstəm wʌz nˌɑːt vˈɛɹi ɹˈɪdʒɪd, ɪnðə sˈɛns ðæt kʌnˈuːhi kʊd bɪkˌʌm kˈæŋkoʊ wɛn ðeɪ ɡɑːt ˈoʊldɚ sˈɪksti sˈɪks, ænd ˌɔːɾəmˈæɾɪkli fɹˈiːd æt vˈɛɹi ˈoʊld ˈeɪdʒ sˈɛvənti sˈɪks bˌʌt ðɪs ɪz ʌnlˈaɪkli æz mˈoʊst pˈiːpəl wʊd nˌɑːt ɹˈiːtʃ ðɪ ˈeɪdʒ ʌv sˈɪksti sˈɪks ænd ˌoʊvɚ dˈʊɹɹɪŋ ðiːz tˈaɪmz, ænd ɹˈaɪəmˌɪn kʊd bɪkˌʌm sˈɛnmɪn æt ðə kˈæŋkoʊ lˈɛvəl ˈæftɚ hˌævɪŋ kəmˈɪɾᵻd sˌʌm kɹˈaɪmz.
This caste system was not very rigid, in the sense that Kunuhi could become Kanko when they got older (66), and automatically freed at very old age (76) but this is unlikely as most people would not reach the age of 66 and over during these times, and Ryōmin could become Senmin (at the Kanko level) after having committed some crimes.