Troubles and worries will negate your ki, and should be left outside the dojo, thus freeing your mind and enabling you to concentrate on your practice. I hope everyone realizes that Aikido training is not just physical but mental also. In fact, Aikido techniques, when performed by high grades, do not rely on their physical but their mental. Of course, not everyone wishes to study this aspect but it's an inescapable part of training in Aikido.
Ki is split into two, positive and negative, and it has other parallels; ying and yan, good and bad, black and white. I am sure many of you have seen "Star Wars" and "The Empire Strikes Back", which mentions the "Force", this can be translated to be the same as Ki. As is seen in the films, if you have the doubt that you can't do something then you will fail, but belief that you can do something is a positive attitude and is usually accompanied by success.
When I first started Aikido I was very impressed with Tohei's book on Ki. The examples used in his book of every day occurance of positive and negative ki assisted me in understanding a little.
A person who is sick is usually negative. A negative person tends to go to another negative person and says something like "Are you also sick?" "I'm suffering as well. It's hard to be sick isn't it?". In this way both people become more negative. Thus a depressed and gloomy person spreads gloom and despondency to other people and makes them negative. Take Marvin the robot from "The Hitch Hikers Guide to the Galaxy".
The converse is also true. A positive person inspires others around him, and they gain his charge and become positive also. Thus the dojo should be filled with positive ki and an negative ki brought to a practice by a student should be overcome. However, students should learn to maintain positive ki all the time. The training for maintaining positive ki is basically to learn to adopt a positive attitude, not only to Aikido, but to every day life. Of course, through Aikido training, your own ki is enhanced by practice and special exercise.
Your mental and physical training is enhanced by a positive attitude or spirit as it has a multiplier effect. Consider your own behaviour in terms of ki, for example, do the dark, wet and cold nights put you off practicing, preferring instead the comfort of the chair in front of the TV?
Andrew Baird Published 1983