With a pair of sharp secateurs. Best done late March though.

It is usually best to cut out the oldest stems completely, since most species' canes die after 3-4 years. Remaining stems can be cut back to side branches, but not so far as bare canes--often, bare canes will not sprout. Removing unwanted sprouts from a running bamboo is a whole other project, though!

Realy you need to dig it up and chop the culm or roots back to the size you want then plant what's left within a special bamboo membrane to keep it in check . I hope your fealing fit and energetic. cutting the shoots will just premote more growth and be very tempery at best . Its ominas that our local garden center no longer sells any kinds of bamboo . its a perfect time to do this job is the only good news . good luck .