many details remain to be clarified , and there are two theories about the zatsuyo (zoyo ): one is that the zatsuyo as well as the soyocho (a tax system under the kinden system , or the equal-field system ) was a basic tax; the other maintains that the labor to the government was basically provided in the form of the saka (labor allocated by rank , 差科 ), a major example of which was the shokueki (職役 ), or the transport of goods ), being a different tax system from the soyocho . 詳細については不明な点が多く、租庸調と並び基本的な税目とであったとする説と基本的な労役は租庸調とは別系統である差科（職役などが代表例）であるとする説がある。
therefore , in the middle of the eleventh century at the latest , a basic foundation was established based on jishi (land rent ) of koden that was leased and determined " genmai " of 3 to per dan (dan betsu san to ) as the basic tax instead of so , and on top of that , a property tax instead of yo , cho , suiko , or zoyo called " junmai " that was collected in kind (some included manufactured items such as silk , cloth , oil ). そのために遅くても11世紀中期には公田を賃租・請作した場合の地子に基づいて、1段＝3斗（段別三斗）を「見米」と称して租に替わる基本的な賦課とし、それに庸・調・出挙・雑搖などに替わる地税賦課を「准米」と呼ばれる代物納（一部は絹・布・油などの手工業品を含む）の形で上乗せすることという基本が確立されることになった。
