Bamboo Plant Question

[Fishboy]

My wife planted a bamboo in a large pot two years ago and the thing is now thoroughly root bound. I don't know the species, but the stems are bright yellow. Anyway, I want to pull this thing out of the pot, but it's like a stone in the center. When I used one of those post hole digging iron bars as a chisel, it just bounced off this rock thing. I don't want to break this pot, but that may be my only choice if bamboo forms a solid corm or such structure.

Do these plants form a solid mass underground? I thought of using a sawsall to cut the mass in fourths and pull them out separately, but wanted to ask you guys if there's any easy way (besides breaking the pot) to get this out. I may sound desperate, but I'll appreciate any thoughts.

Mahalo nui loa,
Brian and Mary
Lynnwood, WA\Discovery Harbour