You'll eventually have more Basjoo than you'll know what to do with. I had 13 last year and by the end of the year I had close to quadruple that many - one plant that was in the ground for its second year had 14 pups at one point. Do a search on how to separate them here on the forum - I have found (thanks to advice here) a digging bar is the way to go. See this thread:
Digging bar - excellent tip!
When possible, always try and take the sword suckers. They'll grow stronger than water suckers (see below for comparison - the one with all the roots is the sword sucker).
These are also some good photos to give you an idea of what's going on underground:
