Yah, You Know a.k.a. Yah, U Know is a song recorded on 5 June 1982 (on the same day as Horny Toad) at Prince's Kiowa Trail Home Studio, Chanhassen MN, USA. It's not known if the track was intended for Prince's next album 1999, or any other project at the time of recording.
The song was released in 2019 as the fourth track on the Vault Tracks part 2 disc of a Deluxe edition of the 1999 album.
Eric Leeds recorded saxophone overdubs on 4 June 1986 at Prince's Galpin Blvd Home Studio in Chanhassen, Minnesota (the day after a configuration of the Dream Factory album was made, the same day Slow Love was recorded and exactly one day shy of 4 years of the original tracking). It's not certain, but likely Atlanta Bliss trumpet was recorded during the same session. It is thought to have been worked on for possible inclusion on Dream Factory, but it was not included on any known configurations of the album.