Once in a very blue moon

Once in a Very Blue Moon is a song written by country singer Patrick Alger & Eugene Levine. It was the title track of Nanci Griffith's 3rd studio album released in 1984. 

Notable covers include ones by Chris Smither, Dolly Parton, Mary Black and by Alger himself (in 1991). 

Full list of covers in Secondhandsongs: https://secondhandsongs.com/performance/4221

Notable covers include: 

• Chris Smithers on his 1984 It Ain't Easy album
• Dolly Parton on her 1985 Real Love album
• Mary Black on her 1987 By the Time It Gets Dark album
• Patrick Alger (one of the song's composers) on his 1991 True Love & Others Stories album
• The Chenille Sisters on their 2007 May I Suggest album

Note: There is a serious error in the chord line for the bridge of this song in Rise Again. It should read: Cmaj7 - Bm Em / C D CD G / 1st / Am - D - (The chords that appear are in the wrong key.)