Sadly (and VERY expensively!), we've become experts on getting rid of bamboo. (And we were the ones who paid to put the bamboo in in the first place - totally loved it, but the variety we chose spread too aggressively.)
If you don't have a Sawzall-type (electric reciprocating saw) tool, you may want to buy/borrow one. They are handy for DIY projects anyway, but we used ours a few years back to literally saw straight into the ground in sort of a 1-foot grid pattern to be able to dig up our bamboo shoots. It took two years, but we were able to finally say that we got it all. The running bamboos really can throw their weight around and spread.
Our seasons and timing might be off from yours - but ours used to spread its roots in the summer. It is best to get the roots while they are soft and new, since the longer they are allowed to remain there, the firmer - and more steel-like - they get. Bamboo roots (ours, anyway) were bright gold when they were new and only grew in the top foot of the soil, so at least we didn't have to dig deeply. We tried to saw/dig after rain, so things would be a bit softer, but you may need to water, if rain is sparse. The roots become so entwined with each other, that it is totally impossible to get a garden tool into the mass. Even the skinny saw blade was challenging to insert at first, but once you get started, you can make yourself access holes to saw into the soil to get at the roots. We didn't really have any rocks, but this could be dangerous if your soil is pebbly. You also have to watch for any underground wiring or plumbing! (Not an issue for us, but...)
If you can get the worst of the roots out, then a yearly check and pull-up of any new ones is much, much (MUCH!) easier. That should keep things under control, but you do have to stay on top of it.
We loved the privacy our bamboo gave us from nearby neighbors, but if we ever plant any again, it will be one of the clumping varieties, not a running one! Good luck - and happy to answer any questions if none of this makes sense! P.S. Even if you wanted to, chemicals don't work. You've gotta get the roots up.
Pam