Much of the Ritsu (the penal code) part of the code book was lost, but the intensive research had been made to collect and restore those missing parts of the code book, and the aggregation of the research was compiled as "Kokushi Taikei" (the compilation of historical and juridical texts from the fourteenth century).
律については多くが散逸しているが、逸文収集が精力的に行われ、その集成が『国史大系』にまとめられている。