guitar-chord（吉他和弦）

Guitar Chord Tool

1. Forward Lookup (Chord Name → Notes)

python3 chord_identifier.py <chord_name>

Example:

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

2. With Chord Diagram

python3 chord_identifier.py <chord_name> --diagram

3. Reverse Lookup (Notes → Chord Name)

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

Example:

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

4. Chord Inversions

python3 chord_identifier.py --inversion <chord_name>

Example:

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

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:

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

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:

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:

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