In the lists
He does not appear in the wazamono lists of the Japanese and English Wikipedia, which follow the Kaihō Kenjaku (懐宝剣尺) of 1797, nor in Tomita Kiyama’s ranking of shintō smiths (1933, published in 1935) translated by the Japanese Sword Index. The Japanese Wikipedia has no article on him, and its article 日本刀 (nihontō) names Hōki no Kami Nobutaka, Masatsune and Ujifusa among the shintō smiths of Owari, not Yasuyuki.
He is not recorded in the Kyōhō meibutsuchō (享保名物帳, Kyōhō meibutsuchō), nor is any work of his recorded as designated a National Treasure or an Important Cultural Property, nor any blade of his in a museum.
Who he is confused with
The Yasuyuki listed in the Kaihō Kenjaku is Yamato no Kami Yasuyuki, a different smith.
What is not on record
None of the sources cited gives his province, his school, his master, his dates, the year of his title or a description of his steel, his temper, his point or his signature.