HONG KONG, China (AFP) — Jiri Prochazka was a football hooligan in his native Czech Republic until martial arts and an ancient Japanese text inspired him to turn from street fighting to cage fighting — and become an Ultimate Fighting Championship (UFC) world champion.

"The Book of Five Rings" was written in 1645 by the master Japanese swordsman Miyamoto Musashi, and when Prochazka was handed a copy about eight years ago he finally found the focus to "become a warrior" after a wildly misspent youth.

"You have to look into yourself, and you have to follow the rules — be honest, be brave, be calm in hard situations," said the 29-year-old Prochazka, of what he has learned from the book and from the "Bushido" Samurai code of discipline that it encourages.

Prochazka became the UFC's first Czech world champion after a thrilling back-and-forth battle with Brazilian light heavyweight Glover Teixeira that went deep into the fifth and final round in Singapore in June.

A battered Prochazka seemed on the verge of defeat to Teixeira, but somehow drew on reserves of strength to apply a choke hold and force the Brazilian veteran into submission.

"Some people say my style is unpredictable," Prochazka told AFP.

"But I'm not doing unpredictable things. I am calm and I just look for the space for attack — where is the weak point of my opponent — and I attack."