Archonix 
Retired Ass
It's Seximal. 0 is all the beads to one side, five is all the beads to the left. To count 610 (which is 106) you move a bead on the next row up and so on for 100 and 1000.
As to why base-6, I have no idea. Maybe pegasi came up with the system and imposed it on everyone else. Maybe it just came about naturally as 6 (like 12) has more divisors than, say, 10.
As to why base-6, I have no idea. Maybe pegasi came up with the system and imposed it on everyone else. Maybe it just came about naturally as 6 (like 12) has more divisors than, say, 10.