Ritsuryō (律令) is the historical law system based on the philosophies of Confucianism and Chinese Legalism in Japan.
During the late Asuka period (late 6th century – 710) and Nara period (710 – 794), the imperial court, trying to replicate China's political system from the Tang Dynasty (618-907), created and enforced some collections of Ritsuryō.
The Ritsuryō system also established a central administrative government, with the Emperor at its head.
In accordance with the legal codes, land as well as citizens were to be "public property" (公地公民). One of the major pillars of the Ritsuryō was the introduction of the Handen-Shūju (班田収受制) system which regulated land ownership. Based on the registration, each citizen over 6 was entitled to a "distributed field", subject to taxation (approx. 3% of crops).
Also a measure for the person with disability was specified by the law. If there was a person with disability in the household, the quantity of crops for tax was reduced depending on his disability degree.
Although collection of the tax was very severe, the state treated a person with disability as a public citizen. However, tax exemption was not complete. Only the burden on the family or the whole village increased. Apparently people unable to make tax payment had to escape from their residence. Even people without disability run away to avoid the tax system.