Complex sentence: Although he is reputed by his detractors (most notably, Gichin Funakoshi) to have been a violent and crude streetfighter, lacking in formal instruction, at one time or anotherr, Motobu was the student of several of Okinawa's most prominent karate practicioners.
Split into simpler sentences: Although he is reputed by his detractors (most notably, Gichin Funakoshi) to have been a violent. MAt one time or anotherr, Motobu was the student of several of Okinawa's most prominent karate practicioners.