What is "aiki-jo"

Aiki-jō ( Kanji: 合気杖 Hiragana: あいきじょう) is the name given specifically to the set of martial art techniques practiced with a jō (a wooden staff about four feet long), practiced according to the principles of aikido. Jō techniques were introduced into aikido by Morihei Ueshiba, aikido's founder, and further developed by Morihiro Saito, one of Ueshiba's most prominent students.