Some masters claim there are techniques hidden within kata so they would be kept secret from the Japanese overlords. The purpose of some techniques in kata may not be obvious but this does mean they were meant to be hidden or secret. In 1868, the "Decree Banning the Wearing of Swords" abolished the samurai class and all its privileges and made it legal for common people to practice karate. Since the first kata was invented around 1800, and karate training became legal in 1868, if kata training ever had to be done in secret, it would have had to be between 1800 and 1868.
In 1868, Japan moved from feudalism to democracy. During this time, the Japanese abandoned many of the aspects of their culture that were attached to feudalism. The class structure, the wearing of swords by samurai, the styling of the hair in to the “top-knot” etc. were all abolished. However, the Japanese authorities also wanted to foster many of the values associated with the past. It was felt that the practice of martial arts would promote health, develop strong sprit, encourage morality, help the Japanese maintain a sense of national identity in the wake of political change and foreign influence, and would be an aid to Japan’s growing army. The development of “sporting” martial arts were supported by the ministry of education and hence arts such as Judo and Kendo were strongly promoted in Japan’s education system.
In 1891, during their medical exam for recruitment into the army, the exceptional physical condition of two young karate exponents (Yabu Kentsu and Hanashiro Chomo) was noted. As a result, the military inquired as to whether Karate would be an aid to the Japanese war machine, as Judo and Kendo had been. This idea was ultimately abandoned due to the disorganization of the karate fraternity, the length of time it took to become competent, and due to fears that the Japanese troops may use their new found skills in brawls. However, at the turn of the twentieth century a group of karate practitioners campaigned to get karate placed onto the Okinawan school system’s curriculum in the belief that young men with healthy bodies and moral character would be far more productive in Japanese society.