Kugen (legal certificate) (公験)
Kugen refers to a kind of certificate issued in the Japanese nation under the ritsuryo codes to give a privilege to specific persons.
A legal certificate issued by the state or its subordinate organization for development, trade, transfer, loss, donation and inheritance of the private land or property. When any change accompanied by legal effect occurred, the party submitted gejo (a form of letter used by lower-class people to make a suggestion to higher ranking people) to kyoshiki (the Capital Bureau) or kokushi (provincial governor) (through Gunji [local magistrates], in many cases), and it was given kohan (公判) by kyoshiki or kokushi to certify it as kugen. Accordingly, the form pursuant to kushikiyomonjo (documents prescribed in Kushiki-ryo [ritsuryo law] in the ritsuryo system) came to be used (because gejo was taking the form of ge [the prescribed form for a written statement submitted to superior government office] of kushiki-ryo). If the object of change had already been provided with kugen, it was compulsory to attach the kugen to gejo, and in the case of loss, a prompt notification to governmental official in charge of issuance of kugen was required to be supplied a certificate confirming the loss.
Particularly, kugen on the ownership of land was called honkugen or konponkugen. For suit, submission of kugen was required, and kugen was taken as the most important evidence.
The Medieval Period
After the mid Heian period, the form of kugen changed because the kushikiyomonjo faded out with the demise of ritsuryo system. Rinji (the Emperor's command), inzen (a decree from the retired Emperor), kansenji (a government edict) and kudashibumi (document issued by a superior or office) issued by the Imperial Court, government official and bakufu (Japanese feudal government headed by a shogun), and moshijo (a document format for communicating something from a lower person to an upper person) to which gedaiando (an approval of landowner written in the margin of the document submitted) was written in, were used in place of kugen, and 'kugen' began to refer to all of those. Those guaranteed various properties and rights of people of all ranks from influential people to ordinary people. Furthermore, certificates by lords of the manor or local magnates and documents related to property and right also began to be called kugen. Kugen were considered to be valid evidence with a recognized legal effect guaranteeing the ownership right to assets, including land; therefore, they were remained valid across generations, and were passed on when any legal changes occurred. Accordingly, one of the principles in lawsuits was that only the transference of a kugen could legally confirm the transfer of an ownership right through assignment or sale.
Kugen was issued by the Imperial Court as a certificate that was given to the Buddhist monks and nuns officially approved by the state when they received doen (identification of monk or nun). After Jianzhen introduced religious precept to establish the kaicho (Certificates of Reception of Buddhist Commandments) system, the meaning of the term was limited to the certificate for the long-term trip for ascetic practices and so on. Kugen came to be rarely issued because soniryo (Regulations for Monks and Nuns) subsequently became a dead letter.