Hmm, this is not as easy as it appears according to what Pheldal writes. I'm German and make music in several bands, Schlager and Rock-Covers. No matter what kind of music, it's mostly that the guitar players call the chords the US/UK way: A - B flat - B - C. For me, being the keyboard player, a 'B' is an 'H' and a 'B flat' is a 'B'. More complex: pheldal speaks of mainland Europe having it the "German" way. I lived in Italy some years, and my band colleagues there called our 'H' resp. 'B' a 'Si' and our 'B' resp. 'B flat' a 'Si bemolle'. I can't imagine of any system to base the app on. Any other thought appreciated. Best regards.