The name BUIKU letteraly means martial evolution, in a freer interpretation but certainly more understandable you can better translate as Budo’s evolution.
This name designeted the Aikido in the latest living years of the Venerable UESHIBA Morihei, Art that saw right at the time a radical transformation and evolution, as the Great Master infused all his work of originatility and diversity in it, building like this a carrying structure to all those techniques and principles, that at first looked so untied together. O-Sensei’s geniality was to have understood in its details, the possibility of the mechanical action of each individual, that is the phisiology of the movement and the possibility that the human anatomy can explain when it is put in the most limite and disparate situations. In fact the study on the possibility of the movement and most of all of its coordination, brought O-Sensei to discover its most secret details, not only, but consequently even to acknowledge the possible negative implications, that from the inner mind, the psyche, and from the external body, the adversity of life, (called stress today), can cause in the body in question, pathologies of different kind, above all psychosomatics.

Still, the Venerable UESHIBA, knew how to make the most of the practice and the reaserch (of course exetensive as it was dealing with human things), bounding spiritual principles with the stages of the human evolution and maturity; he succeed to visualize the ethereal principles of the Yin and the Yang , giving to them a pratical body and an understandable way for everybody through the tecniques of his last ” Aikido”. Why do I say last? the answer is certainly cointained in its chance.
As a matter of fact with this name we recognize a lot of Japanese martial schools, some of which they feel to be usurped of the name in comparison to UESHIBA’s art. The reason of this denomination is surely wrapped in mystery, even if we can guess the O-sensei liked this name very much, and we know for sure that for many years His Art was called UESHIBA Ryu. What it is certain is that the Great Master did not care so much about the name of his art as he did for his practice. The necessity to tie a name to the practice became impellent when the first Master’s pupils started to leave him to open their own teaching centre of that Jutsu. So may be by chance may be because it had to be, the name Aikido was tied to the destiny of that school. But that’s why there are so many differences among the various Aikido’s schools.
In fact even if they all have the same name, as you can understand, not all have followed the evolution and the study of the Great Master, quite the contrary, they were only few. Many schools boast the accuracy of the original techiniques, of the loyal suburi and kata, quoted also by manuscripts etc., but this doesn’t mean anything. Nobody can doubt of the capability of skillful pupils as: TOMIKI, MOCHIZUCHI, SHIODA, THOEI, ABE, SAITO, OSAWA, ICHIZUKI, TADA, without talking of the same UESHIBA’s son, KISHOMARU, Doshu of the Aikikai, school founded by him when his father was still in the most active stage of His personal research. It is therefore very easy to understand the existence of the Aikido schools as: the YOSHIN KAI, the YOSEIKAN, the TOMIKI at the KODOKAN, the SHIN TOITSU AIKIDO, better known as KI NO KEN KYU KAI, and the international AIKIKAI and many more. Without mentioning all the other schools from which UESHIBA Sensei took the remark as a starting point for his study. As the pupils left the Master, more and more styles and schools started, really very few were the ones who followed the Master in his evolution.
Among whom, the person who stayed with him till the end and the one who inherit his last will was KOBAYASHI HIROKAZU.
Therefore inevitably another school started, even if realistic the Master KOBAYASHI has always acted inside the AIKIKAI, the BUIKUKAI of the south of Japan in Osaka, the AIKIDO UNION KOBAYASHI in ITALY (today known as BUIKUKAI of ITALY, north and south), and gathers numerous groups even from POLAND, HUNGARY, GERMANY, etc. and the ACADEMIE AUTONOME D’AIKIDO in FRANCE with many more members in the world.