An 8-string ukulele has every string doubled and creates a big, giant, rich sound. It’s similar to a 12-string guitar with a course for each string.
A course is two strings that are treated as one. They are played at the same time and usually tuned to the same note.
If you examine the string layout on a classic Kamaka HF-38, you can see that they are grouped in twos. Each pair of strings takes the place of a single string on a normal ukulele.
Here it is in a strumming setting as implemented by Nā Hoa.
The nice thing about the 8-string is that its tuning is pretty much locked in to convention. Nine times our of ten, an 8-string ukulele is tuned
gG cC EE AA.
To break that down, the top course is tuned high-g and low-G – with the high-g closest to the ceiling. The C course is tuned with a high-c and a normal C – with the high-c closest to the ceiling. Both the E and A courses are tuned in unison to the normal GCEA pitches.
dD gG BB EE.