Maruyama Sensei was astonished when the judo and karate students actually challenged and resisted during the application of Aikido technique, such behavior was unknown in Japan.  Sensei Maruyama was also challenged to defend against kicks and jab punches from karate students, these types of attacks were never practiced in Japan.  His inability to respond  effectively caused the students to resist him more.  In consequence, Maruyama Sensei's first few years in the USA were very difficult. 

     Maruyama Sensei has caught Ueshiba's feeling for using only necessary strength, describing it in terms of using the minimum effort necessary to achieve maximum results, but now he applies that feeling to techniques responsive to the realities of modern unarmed fighting.  Kokikai Aikido practice is characterized by realistic, focused attacks, fluid responses that employ timing and rhythm to take the opponent's balance completely before the application of a throwing technique.