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Tekki Nidan (鉄騎二段) - "Iron Horseman, Second Level" - "Железный всадник, второй уровень".
Original name for Tekki was Naihanchi. Several versions exist about creation of Naihanchi (Naihanchi Shodan), Naihanchi Nidan and Naihanchi Sandan. Original Naihanchi kata is often credited to Matsumura Sokon (1809-1902), who probably taught Naihanchi to Itosu Yasutsune.
One version says that these two kata were created by Itosu Yasutsune on the basis of original Naihanchi. Another version says that the original Naihanchi was broken into three parts (possibly by Itosu Yasutsune, or Tokumine Pechin, or Motobu Choki).
Funakoshi Gichin learned Naihanchi kata (Naihanchi Shodan, Naihanchi Nidan, Naihanchi Sandan) from Itosu Yasutsune and later renamed them as Tekki.
Hirokazu Kanazawa in his book "Shotokan Karate International Kata (Vol. 1)" says: "If one practices daily every morning and evening Tekki he may be called a karate-ka".
Nakayama Masatoshi "Best Karate. Vol. 5. Heian, Tekki"
Hirokazu Kanazawa "Shotokan Karate International Kata (Vol. 2)"
Fiore Tartaglia "Shôtôkan-Kata ab dem Schwarzgurt"
THE SHOTOKAN WAY – The Online Shotokan Karate Magazine: Tekki Nidan
Tekki Nidan performed by Funakoshi Gichin Sensei, 1924
Tekki Nidan performed by Shirai Hiroshi Sensei in the JKA kata film, 1960-1962