When Kagekatsu inherited the rank of Danjo-Shohitsu from Kenshin, some say that the two relevant letters were written in Kagekatsu's handwriting; that is to say Kagekatsu forged those letters in order to justify himself (The History of Niigata Prefecture, The History of Joetsu City: Complete History I: The Medieval Period).
景勝が弾正少弼を謙信から譲り受けた際の2通の書状が、景勝自身の筆跡と同じであるとし、景勝が自己を正当化する為、偽作したとの説（「新潟県史」「上越市史通史編2中世」）がある。