Ai means to harmonize and ki means energy thus aiki is about harmonizing energy. This can be as in Aikido – harmonizing ones energy with the attacker but it also can be harmonizing all ones energy into a single effort. Either way all martial arts, whether they emphasize it or not, use aiki. Aiki is both physical and mental – blending with the attackers energy or intent. Shoshin Ryu uses aiki in many of its techniques and drills the principles home with Taiatari (as series of attacks that emphasis various blending techniques).