Rank levels in Karate are called Kyu, pronounced [Q], meaning class. A student starts at 10th Kyu "no rank" and works their way down to 1st Kyu. Once a student reaches black belt level, the ranking changes to Dan, pronounced [don], meaning step. You start at 1st Dan and work your way up. Shodan means 1st step or most commonly known in English as 1st degree black belt. Many instructors say that a student's karate training starts at black belt hence calling it 1st step.
As you can see in the diagram below, there is a rank called Shodan Ho which means "Probationary". One must wear a probationary blackbelt for one year before given an offical black belt. Junior students in the Genbu-Kai Organization receive a red belt when they reach Shodan. A red belt is equivalent to a junior black belt in other schools. Once a junior student reaches adulthood and shows the necessary quality and character, they may test for a black belt.