Provided that your boy had his parents support to take him to and from classes, provided he had a good teacher, was athletically inclined, was not physically or mentally challenged and did get it, at 17 he could be a Shodan. My son (Lex's brother) was 7 when he started and was promoted to black belt at 16. Much more went into his training than just the things you stated. But because of this he was always better at martial arts than any of his peers however there is also a maturity level that has to be achieved which is not achieved before the age of 16, and 16 is really pushing it with 17 or 18 years old being the average. So if you are trying to justify kids' black belts it is my experience teaching kids that they do not have the mental understanding to be what it takes to be a black belt. I also have two other sons who started at about the same age, got the same opportunities training, one of whom quit at blue belt because he did not like the discipline and didn't want to conform and the other had challenges to overcome so it took him a little longer and he made black belt at 18.
Hard to say... A lot depends on the person and whether they have natural talent or are not really gifted at karate. I know some people who made shodan before I did and they claimed to only practice outside of class if they were preparing for a tournament. They had more natural ability and were more coordinated than me. There are also people who have been training for longer than me and train more than me but are lower rank. Also it depends on if you piss of the instructor or not. Then people don't normally progress steadily. There are often periods of plateaus. There are also periods where people put in intense effort- I always like to watch the high school students who are trying desperately to get their shodan before they go out of state to college. Many of them if they put that much effort in sooner would have advanced so much quicker. For other people promoting is like pulling teeth. I hate promoting and I have been forced to promote at times against my will.
If I HAD to give an answer I would say brown belt could be realistic (about 1 or two ranks from being a black belt)
So here is something people forget, a black belt does not transfer from one style to another. It does have a specific meaning, Dani was taken from the Go game and a dani (black belt) is at the professional level of that style. Nobody, but a member of that group can say if the person is at professional standing it depends on the art. Chances are that if they started at 7, trained hard under a QUALIFIED instructor they would be at a professional level at 17. Check this out for more information
http://karatedr.com/a-modest-proposal-on...
Some people train for several decades and never even reach their first dan. No one can tell you what rank you would be, no matter how much you train. Correct training has much more to do with your ability than how much you train. Every one progresses at different rates. It is not something that a formula can determine. Rank is not based on time, but on knowledge and ability.
EDIT: No you don't want a more specific answer, you want someone to say what you want to hear. Sorry, but the reality is what it is.
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Most people never earn the rank of a black belt. Everyone learns at their own rate. Some people learn faster or slower than others. There is no way to determine what a person rank should be using your terms. It is impossible to gauge in that manner.
generally karate schools arrange grading examinations on each 6 months.
white
green
blue
brown
black
is the most common belts.
now you can calculate
My brother was a black belt at that point. And that's when he started.
Imagine: a boy who started Karate at the age of 7, has 2 hours per week of classes, trains 30 minutes every day at home and puts a lot of effort into it. What belt would he be at the age of 17?
