In my career life, I am the manager of a software engineering team for a state government agency. Developing software for state government is an interesting occupation, full of daily surprises, unexpected course corrections, legislative mandates, customers with high expectations, and many other lively activities. Delivering quality software within a reasonable time frame and meeting the business requirements of my customers is a constant challenge. Our Bureau Chief has a saying written on his whiteboard: "Good, Fast, Cheap, Pick 2." He likes to remind customers that they can usually only pick, at the most, 2 of the 3 items. Life is an exercise in compromise and software development is certainly no exception.
Kishaba Chokei, Sensei, had a saying that karate must have Speed, Power and Grace to be considered good. (I am paraphrasing, of course) Karate techniques should be quick enough to reach their intended target before the target can reach you. Techniques must be delivered with sufficient power to inflict appropriate damage to the intended target. And, techniques must be delivered in a way that utilizes the whole body in a graceful, interconnected way leaving the practitioner free to move in any direction and perform technique after technique.
Without Speed, Power and Grace working together, Karate is lacking.
You can see these forces working together in many sports and performing arts. Ballet is a good example of Speed, Power and Grace working together to produce the perfect Grand Jete. Another example is the execution of a perfect swing to yield a home run in Baseball. Without any one of these three elements, the ballet jump would fizzle and the bat swing would foul.
Koshi is the guiding force that brings Speed, Power and Grace together to make the perfect karate technique. Moving from a tightly compressed center and rotating in multiple planes like a gyroscope, Koshi directs the power, controls the speed and enables gracefulness for truly great karate.
Here's an exercise you can try the next time you practice Kata:
Perform a kata with speed only. Don't try to put any power in the techniques. Don't worry about how good it looks. Just try to get from point A to point B as quickly as possible. Next, try the same kata with power only. Make as much power as you can. Don't worry about being fast or beautiful in your execution of the kata. Then, repeat the kata with gracefulness. Be smooth and artistic. Flow like water and don't try to make it powerful or fast. Finally, combine all 3 elements together in a final performance of the kata. Analyze what body dynamics you had to employ to make it feel right. Repeat this practice frequently and you will make amazing progress.
For your Karate, don't compromise. Pick 3!