To learn Iroha - (sasaki, feat. 鏡音リン) 炉心融解 chords, your practice should emphasize these chord progressions: A, G#, C#m, A, C#m, G# and A. To build a solid grasp, start slowly at 83 BPM and then match the original tempo of 166 BPM. Fine-tune the capo based on your vocal range, ensuring it complements the key of C# Minor.