Originally in Edo bakufu, yuhitsu served as close adviser to Seii Taishogun (literally, "great general who subdues the barbarians") writing gonaisho (a letter issued over the signature of the shogun), hosho (a document for informing lower-rank people of the decision of upper people such as an emperor or shogun), making a fair copy of hatto (law) and preparing official documents under the orders of roju (member of shogun's council of elders), but when Tsunayoshi TOKUGAWA became shogun, he brought yuhitsu of the time of Tatebayashi Domain to Edo-jo Castle and involved in his secrets instead of existing yuhitsu.
元々江戸幕府には右筆の職が存在して征夷大将軍の側近として御内書・奉書の執筆や法度浄書などを行い、また老中などの指示に従って公文書などの作成などを担当したが、徳川綱吉が将軍になると、館林藩時代の右筆を江戸城に連れてきて、従来の右筆に代わって自己の機密のことを関与させた。