This is not correct.  In the professional ranks 1p is often no weaker than 9p because often the young players start out at 1p and are very strong because selection pressure is much greater.  The 9p rank in Japan also came partly out of just playing a lot for a lot of years so that accomplishment was not as great as it seems.  In any case, active professional players for the most part are not dramatically stronger than one another.  The range for the most part is about 2 stones, maybe 3.<p>Even though Fan Hui is not an active professional in the traditional sense this is an absolutely huge accomplishment and leap in playing ability by computers.  BTW, Michael Redmond is not particularly strong by professional standards.<p>(Edit: The correlation between strength and rank now as noted below is due to promotions more often coming from acheivements:  If you win at X you get promoted to 7p immediately, if you win at Y you get promoted to 9p. You cannot win a big tournament and keep your low rank. Here is an example of someone who went from 3p to 9p in one match: <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Fan_Tingyu" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Fan_Tingyu</a>.  But professionals cannot give each other 6 stone handicaps when one is 9p and the other is 3p)