The bouzouki first became popular in Irish music in the 1970s. The so called Irish bouzouki is an adaptation of the much older original Greek stringinstrument. The three main differences between the Irish bouzouki and Greek bouzouki lie in the shape of the body, the length of the fingerboard and the tuning of the strings.
Greek bouzoukis feature the typical rounded back, and can be either three course (6 string) or four course (8 string) instruments. Greek bouzoukis are typically slightly larger instruments with a longer scale length of approximately 27 frets. The Irish bouzouki features a shallow, flat back which some find easier to hold. Irish bouzoukis typically feature a shorter scale length of approximately 24 frets.
The string sets or string pairs on a Greek bouzouki are typically tuned to octave intervals. Standard tuning for a Greek bouzouki is CFAD. Irish bouzouki pairs are tuned in unison to GDAE or GDAD. This tuning lends itself well to accompanying traditional Irish music.