The man who answered the luck question honestly, and kept answering.
If you have ever typed a rules question into a search bar late at night, you have very likely landed on Tom Sloper's pages. He came to mahjong sideways, through a career making video games, producing the Shanghai tile matching series at Activision for the better part of a decade. He went on to play tournaments in Japan, Europe, China and here at home, lectured on the game at the Smithsonian, and wrote The Red Dragon & The West Wind.
His great gift is the least glamorous one: he wrote the questions and the answers down. His FAQs and his long running column at sloperama.com have answered strangers for more than a quarter century, and his papers are kept at The Strong National Museum of Play. On luck he is honest. The better player wins more often, he writes, and even the best are "subject to the vagaries of chance."
Written from what the letter said. Read the letter for the whole of it.