The main basis for why Stu changed from gin to poker was that Stu was a little too skilled at it. So good in fact, that no one was able equal him. Even the apparently professionals who were meant to be the best at gin were beat when they competed against Mr. Ungar. One of these gin player was Harry Stein, nicknamed, "Yonkie". Harry Stein suffered such a humiliating defeat at the hands of Stu Ungar that he allegedly stopped playing it as a pro and never resurfaced at a gin rummy tournament.
Certainly, with a reputation like that it was not long before players became weary of gambling against stu. He could find no games and in his bleakness he began doing something no one had attempted prior. He offered beginning handicaps to likely competitors with the wish that they might compete against him if they thought they held an edge. He deliberately started from a bad position and one account has it that he even competed against a consistent cheater. Mid contest, he get a few words of wisdom that the cheater was at it once more but mr. ungar guaranteed that he deduced of the cheating and he would still actually win, which of course, he did.
The same problem followed Stu Ungar into sin city. He won so frequently that the poker rooms started requesting that he not to wager in their rooms anymore. The explanation why was that other casino clients refused to be seated at the table if Stu was playing.
Stu Ungar is recollected more for his achievements in texas holdem poker but he always said that he was far better at gin rummy.
He beat Doyle Brunson in the WSOP in Nineteen Eighty to become the youngest world camp. Due to his features that made him appear far younger than he actually was, he got the nickname, "The Kid".