“Great tool for learning, teaching or composing. 
Appropriate for musicians of all levels. I recommend!:)”

~ Tadej Košir

“Very innovative!
I like the simple visual depiction of the links between chords. Featured aren’t just the basic chords, but also more complex musical concepts, which we unfortunately rarely hear in popular music, such as secondary dominants and modal interchange. Additionally, the back of the card contains chord diagrams with corresponding scale tones. There really is a lot of useful information “packaged” into one card. I will definitely recommend chord_files to my students and colleagues. In my opinion, this card should be part of every guitar case!”

~ Primož Grašič

“A great tool that introduces a wide array of possibilities for combining chords, 
which you can safely use in chord progressions…
An exceptional tool for creating and understanding chord and harmonic structures,
which frequently represent the basis of melodic progressions.”

~ Igor Bezget