A bo staff, sometimes called simply a bo, is a long, thin stick. Most traditional martial arts include instruction on how to use the bo as a weapon. While some of this instruction involves partner work, most training revolves around kata, which are choreographed, one-person routines. Kata competitions are common at martial arts tournaments. Most bo kata competitions require that your bring your own bo and that that bo meets the competition's specific guidelines. Choosing a bo for competition requires you to balance your needs with the rules of the organization sponsoring the competition.
Read the official rulebook for the competition you will be attending. Some organizations specify size, weight and material for the bo staffs they allow in competition. If you can't find a copy of the rulebook, call the tournament organizer and ask about weapons specifications.
Talk to someone who competes regularly in the kind of competition you plan to attend. Ask whether a certain style of bo is most common. Some organizations use only traditional wood bos. Others use bos made of modern synthetics. Don't bring a synthetic bo to a traditional competition or a wood bo to a competition that favors flashy, synthetic bos.
Talk to the senior people in your style of martial arts. Determine whether they use a straight bo or a tapered one, a long bo or a short one, a bamboo or wood bo or a synthetic one. The length and type of bo is determined by the kind of martial art you study and the kind of kata you do.
Decide whether you want a custom bo or a mass-produced bo. Beginners should start with a mass-produced bo. When they get good enough to begin to have opinions about how a bo handles, they will be able to select a custom bo that suits their personal style of movement.