Kata are predefined, specific patterns of movement that incorporate and encapsulate martial techniques, concepts, and applications. The exact movements of a kata often vary from one organization to another, and even from one school to another within the same organization. The variations can range from gross deviations apparent to the untrained observer to very subtle minutiae. In his 1977 book on Wadō-ryū (published in English in 1997), Ōtsuka Sensei declared only nine official kata for Wadō-ryū: Pinan Shodan, Pinan Nidan, Pinan Sandan, Pinan Yondan, Pinan Godan, Kūsankū, Naihanchi, Chintō, and Seishan. Within his text, Ōtsuka Sensei provides detailed notes on the performance of these kata, which has resulted in less deviation across organizations on their performance. However, Ōtsuka Sensei did teach other kata. Perhaps because Ōtsuka Sensei did not provide specific notes for the performance of other kata in his text, there is greater variation in these other kata across organizations and schools.