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Piano chords · Blues & boogie

I Don’t Know Why (I Just Do): piano accompaniment sheet music

By Frank Sinatra

  • Bb major
  • 4/4
  • 76 BPM
  • Easy
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Left hand Velvet jazzThe right hand sings the tuneChords the loop the song repeats most

Play the full song with sheet music

I Don’t Know Why (I Just Do) written out as piano music: the I – II7 – ii – V7 loop in Bb major for both hands, with chord names and finger numbers. Press play and follow the cursor. The left hand plays velvet jazz (lh shell voicings (1-7 / 1-3)), and the right hand sings the tune.

I Don’t Know Why (I Just Do) chord chart

The loop once round, bar by bar, in Bb major. The roman numeral says the chord's place in the key, so the same chart works in any key.

BarChordNumeralNotes
1BbIBb D F
2C7II7C E G Bb
3CmiiC Eb G
4F7V7F A C Eb

What the sheet music shows

The grand staff: the right hand on the treble staff, the left hand on the bass staff, with the chord names above and a finger number on each note (1 is the thumb). It is the accompaniment: velvet jazz (lh shell voicings (1-7 / 1-3)) in the left hand, with the right hand free for the melody, over the Bb – C7 – Cm – F7 chords.

Press play and a cursor follows the music. Above it, Colours paints each note in its key’s colour and Note names writes its letter on its head.

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Questions about I Don’t Know Why (I Just Do)

Does the sheet music for I Don’t Know Why (I Just Do) have finger numbers?

Yes: every note of both hands has its finger number, 1 being the thumb. To read the notes alone, turn Fingers off above the music.

What chords are in I Don’t Know Why (I Just Do)?

The loop is Bb – C7 – Cm – F7 (I – II7 – ii – V7) in Bb major, and the song ends on Eb – F – Bb.

What key is I Don’t Know Why (I Just Do) in?

Bb major, at about 76 beats a minute in 4/4.

What does the left hand play in I Don’t Know Why (I Just Do)?

Velvet jazz: lh shell voicings (1-7 / 1-3), an easy pattern. It follows the chords, so the same shape works for every bar.

Is I Don’t Know Why (I Just Do) easy to play on piano?

Yes. Both hands play easy patterns over 4 chords. Learn the chords first, then add one hand at a time.

Made from one arrangement of this song: the left and right hands are the patterns these scores repeat most.