We need to be receptive of our inner center, our inner certainty, to be able to do the Karate movements as easily as if we had invented them ourselves. If we can't feel this instinct for what is the correct technique and delivery, then we're on the wrong track and perseverance can't compensate for it. Practising incorrectly only makes you better at doing the technique incorrectly.
Man's inner root in the Kata is his center. It is called tanden in Japanese (dantian in Chinese). It is also called Seika no itten, Seika tanden or Kikai tanden. It is located inside the body, in the middle of it, approximately three finger widths down from the navel or bellybutton. It is also the center of gravity of the body.
The Chinese or Japanese kanji for the center mean 'the red rice field'. Rice is the prime staple in that part of the world and it is a symbol of life energy. A whole red field of it expresses a vast amount of powerful life energy. Kikai means 'Ocean of ki', tanden is therefore an ocean of ki in your center.
Seika means 'below the navel', so seika tanden specifies which center it is, since some Eastern traditions have several. Seika no itten means 'the one point below the navel', stressing the importance of always sticking to it, making it the center of one's actions. The Indian word svadhisthana can be translated to 'The dwelling of the Self'.
In Karate, as in most traditional martial arts it is the tanden, the center that is most important. You have to find, develop and express your center in all the Kata. It is true about all budo, not just Karate. The center is more than just a center of balance, or the focus point of your breathing. It is an internal fail-safe compass, the birthplace of all martial techniques and of one's own expression of the art. You need to be true to your center. Then the rest of the progress in your 'Do', (the path of your self-realization) - your way), without it, you are unable to go beyond the mere punch kick boundary.
It is from the center that the Karate techniques emerge, as if born from it. The essence of the techniques is the relationship between the center of tori, (the defender), and uke, (the attacker). To regard Karate without Tanden is to limit development of it, nothing is more important in Karate, than working with one's center.
To complete a circle, you must have a center. Techniques are born in the center and spring from the center.