Guitar Chord

Guitar chord toolkit with chord identification, chord diagrams, capo calculation, and more. Features: Identify chord from notes (reverse lookup) Look up notes and diagrams from chord name View chord inversions View drop2 voicings View scales and scale diagrams Capo transposition calculator

Guitar Chord Tool

1. Forward Lookup (Chord Name → Notes)

bash

python3 chord_identifier.py <chord_name>

Example:

text

python3 chord_identifier.py Cmaj7
→ **Cmaj7**
  Notes: C, E, G, B

2. With Chord Diagram

bash

python3 chord_identifier.py <chord_name> --diagram

3. Reverse Lookup (Notes → Chord Name)

bash

python3 chord_identifier.py --identify <note1> [note2] ...

Example:

text

python3 chord_identifier.py --identify C E G B
→ Result:
  • Cmaj7

4. Chord Inversions

bash

python3 chord_identifier.py --inversion <chord_name>

Example:

text

python3 chord_identifier.py --inversion C7
→ **C7** inversions:
  Root: C, E, G, A#
  1st: E, G, A#, C
  2nd: G, A#, C, E
  3rd: A#, C, E, G

5. Drop2 Voicings

bash

python3 chord_identifier.py --drop2 <chord_name>

Drop2 是一种常见的吉他扩展和弦 voicing：把七和弦的第二高音（纯五度）降一个八度，产生更"开阔"的音色。

Example:

text

python3 chord_identifier.py --drop2 Cmaj7
→ **Cmaj7 大七** Drop2 Voicings:
  原位: C, E, G, B
  Drop2: C, G, B, E
  
  常见 Guitar Voicings:
  Root pos.: X-3-2-1-1-0 → C,G,B,E
  1st inv.: X-X-0-2-1-0 → E,C,G,B
  ...

6. Scale Lookup

bash

python3 chord_identifier.py --scale "<scale>"
python3 chord_identifier.py --scale "<scale>" --diagram

Supported scales:

• major, minor, harmonic_minor, melodic_minor
• pentatonic_major, pentatonic_minor, blues
• dorian, phrygian, lydian, mixolydian, locrian

Example:

text

python3 chord_identifier.py --scale "C major"
→ **C Major**
  Scale: C, D, E, F, G, A, B

7. Capo Calculator

Formula: Actual Pitch = Open Chord Pitch + Capo Fret

Quick Reference:

Chord	1st	2nd	3rd	4th
C	C#/Db	D	D#/Eb	E
G	G#/Ab	A	A#/Bb	C
Am	A#/Bb	B	C	C#/Db

Supported Chord Types

• Triads: major, minor, diminished, augmented, sus2, sus4
• Sevenths: maj7, 7, m7, m7b5, dim7, aug7, maj7#5, 7#5, 7b5, mMaj7
• Ninths: maj9, 9, m9

Note Formats

Supports:

• Natural: C, D, E, F, G, A, B
• Sharps: C#, D#, F#, G#, A#
• Flats: Db, Eb, Gb, Ab, Bb
• Symbols: ♯ (sharp), ♭ (flat)
• Case insensitive