Around the 9th or 10th century, the Ritsuryo system (a system of centralized government based on the ritsuryo code) and the Soyocho tax system collapsed and as a result, the taxes due changed into kanmotsu (tribute goods paid as taxes or tithes) and zatsueki (odd-job tasks).
9世紀～10世紀ごろ、律令制の解体にともなって、律令上の租税体系である租庸調制も次第に崩壊し、官物・雑役へと変質していった。