Photo: Bo-geri performed by Higa Mitsue, Okinawa, 1983.
Bo-geri is a lost technique except for Motobu Udundi, although it has been transmitted since the era of Matsumura Sokon. It is similar to axe kick of Kyokushin Karate, but the axe kick was made in about 1987. Therefore it is a modern technique. And Bo-geri is done to various directions including the opponent from behind.
“Matsumura, Tōma, and Nomura were all martial artists of the same era. Matsumura Sensei was known by the people as a man of unparalleled bravery. He was from the Bu-clan, his Chinese-style name was Seitatsu and his personal pen name was Unyū. He freely handled his footwork and was excellent in kicking upwards.
Occasionally, when a comrade tried to restrain him by throwing his arms around him from behind, although Matsumura Sensei could not use his hands, he freely kicked up with his legs on the left and on the right. In this way he kicked down the person who threw his arms around him from behind”.
Choki Motobu, Andreas Quast, (2017), Martial Artists of Ryukyu: A Legacy by Motobu Choki (Ryukyu Bugei Book 3) (English Edition)