By the final session of the London MCR Championship, Professor Moriarty has taken the first position with a tremendous lead of 4 table points and 100 game points above second place, who is Sherlock Holmes. Sherlock can win the championship only under the rarest of circumstances: Sherlock must win his last table, and Moriarty must lose it. Luckily for Holmes, the two meet at the same table.

Before the last deal of the table, and of the whole championship, a miracle for Sherlock was beginning to take shape. Sherlock (East) has +90, Moriarty (South) has -39, Mrs. Hudson (West) has -21, and Moran (North) has -30 points. Sherlock, after winning first deals, has focused entirely on calling mahjong against Moriarty's discards in order to secure his position.

By the middle of a deal, Sherlock is waiting with this concealed hand -- , melded -- four flowers. Moriarty, on the right, has melded three sets including a dragon pung.

The situation is very clear: Sherlock can win from the wall with any hand, from Mrs. Hudson with a hand which scores no more than 17 points, or from Moran with a hand which scores no more than 8. If Sherlock wins from Moran any more than 8 points, Moriarty will bump up to 3rd place, earning him 1 TP, and winning him the championship. Sherlock's chances to win also include a "Hu" by either Moran or Mrs. Hudson, but only if they win with a small hand.

Suddenly, Mrs. Hudson discards . Sherlock cannot declare "Hu" at this time since his hand worth 26 points, and that against Mrs. Hudson would be too upsetting. With Mrs. Hudson sitting at North, then the best choice would be to declare Chow , discard  and wait for a future opportunity. So, Sherlock passes. In one turn Moriarty melds another set so he has four melded sets with two clear points, so he can now clearly win on any discard. In two moves, thunder and lightning struck: Moran on the left of Sherlock discards  and Moriarty on the right declares "Hu".

"So, the London Championship was won by Moriarty?" asked Watson at home.

"No way," Sherlock replied, showing the Champion's Cup.

"But how?"

"The player should know the "Green Book", it is the Bible and the law for the mahjong player."

Question (): Please, explain what happened, and how Sherlock managed to win championship?