Akagi loses the fatal total amount (for someone of his build, at least) of 2000cc of blood in the fifth session against Washizu. He crumples on top of the tiles, while Ohgi remembers his wager of an arm if Akagi should lose. Washizu grabs a ceremonial sword, ready to lop off Ohgi's limb, while Yasuoka looks on in horror. Just as the sword comes down, there is a shuffling of the tiles. Everybody freezes. Akagi has literally come back from the dead. Needless to say, Ohgi and Yasuoka are overjoyed, and Washizu is pissed.
This moment is repeated in Volume 24, minus the sword part.
There's actually at least one per arc, but one that stands out is during the Fake Akagi/Urabe arc, where Akagi pons and chis his way down to a single wait on a tile, basically declaring that he is in tenpai. With that, he gets up and walks away from the table, knowing Urabe will play his winning tile the next turn. And he does. Did I mention that Urabe was playing it safe, and therefore could have played any of the 14 tiles in his hand? And that this was the last round of a 32-million Yen (320 mil today) gamble?
Allong with this, he then proceeds to explain to everyone how he deduced that Urabe would play that specfic piece, Detail by Detail. Everyone is natrually stunned at his calculations.